0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Original Article |

Autologous and Heterologous Blood Transfusion in Head and Neck Cancer Surgery FREE

Melinda S. Moir, MD; Ravi N. Samy, MD; Matthew M. Hanasono, MD; David J. Terris, MD
[+] Author Affiliations

From the Department of Surgery, Division of Otolaryngology–Head and Neck Surgery, Stanford University Medical Center, Stanford, Calif.


Arch Otolaryngol Head Neck Surg. 1999;125(8):864-868. doi:10.1001/archotol.125.8.864.
Text Size: A A A
Published online

Objective  To determine if the use of autologous blood ameliorates the increased risk for cancer recurrence that has been associated with perioperative blood transfusion.

Design  Retrospective medical record review.

Setting  Tertiary care hospital.

Patients  One hundred sixty-five consecutive patients with stages II to IV squamous cell carcinoma of the head and neck treated surgically at a university hospital from January 1, 1989, through December 31, 1994.

Main Outcome Measures  We evaluated the impact of perioperative autologous and heterologous blood transfusion and 10 other variables on recurrence. Univariate and multivariate analyses were used.

Results  Heterologous blood recipients had a 59% recurrence rate, whereas those who had received autologous blood or no transfusion had recurrence rates of 33% and 35%, respectively. The following 4 variables had a statistically significant association with recurrence by multivariate analysis: previous treatment of current malignancy (P<.001); receipt of heterologous blood (P=.04); positive margin (P=.04); and nodal disease (P=.04). The receipt of heterologous blood was associated with a 40% increased risk for recurrence.

Conclusion  Autologous blood products should be used during head and neck cancer surgery if possible when transfusion is necessary.

Figures in this Article

THE IMMUNOSUPPRESSIVE effect of allogeneic blood transfusion was originally described in the transplant literature, when improved renal allograft survival following blood transfusion was recognized.1 In 1981, Gantt2 postulated that depression of the immune system associated with blood transfusion may be deleterious in patients with malignant tumors. Since that time, a number of investigators have reported increased recurrence rates in patients with malignant colorectal, lung, renal, and breast disease who received perioperative heterologous blood. This association has been questioned by some reports.3,4 Twelve previous, retrospective studies compare the relationship between recurrence rates and heterologous blood transfusion in patients with squamous cell carcinoma of the head and neck (SCCHN).516 Nine of them, using univariate analysis, show a statistically significant association between blood transfusion and recurrence.816

The use of heterologous blood has risks other than immunosuppression, including blood-borne infections and transfusion reactions. For these reasons, preoperative autologous blood donation has gained popularity. The relationship between autologous blood transfusion and cancer recurrence has not been well studied. It has been suggested that even autologous blood transfusion may have immunomodulatory effects, possibly because of changes that occur during the storage and processing of blood products.17,18 The effect of autologous blood transfusion in surgically treated patients with SCCHN has not been examined. Our goal was to determine if the use of autologous blood diminishes the risk associated with heterologous blood transfusion in patients with SCCHN.

The medical records of all patients treated surgically for SCCHN at Stanford University Medical Center, Stanford, Calif, from January 1, 1989, through December 31, 1994, were reviewed. Patients with salivary gland, thyroid, or other non–squamous cell malignant disease were not included. Patients were excluded from the study for the following reasons: (1) in situ and stage I SCCHN, (2) postoperative death unrelated to recurrent disease, (3) presence of distant metastases at the time of surgery, (4) synchronous primary tumors, and (5) insufficient (<2-year) follow-up or incomplete medical records.

Numerous data were obtained for each patient, including whether they had a postoperative recurrence, the number of units of blood transfused, the time of transfusion, and the type of blood product (autologous blood vs heterologous whole blood, packed red blood cells, or fresh frozen plasma). Patients with recurrent disease at the time of surgery who had failed previous nonsurgical or surgical treatment were included, and previous treatment of the current malignancy was used as a separate variable in the statistical analysis. Tumor staging was based on the American Joint Committee on Cancer 1989 guidelines. Pathology reports were reviewed for grade, node status, and margins. The site of the malignant neoplasm (oral cavity, oropharynx, nasopharynx, or hypopharynx or larynx) was recorded. Treatment with radiotherapy or chemotherapy in conjunction with surgery was also noted. Other variables included age, sex, preoperative hematocrit value, and estimated surgical blood loss.

A univariate (χ2) analysis was performed on transfusion status, previous treatment of current malignancy, stage, grade, node status, margin status, site, age, sex, preoperative hematocrit value, and estimated blood loss, with recurrence serving as the dependent variable. A contingency table analysis was used for the nominal variables, and a simple logistic regression was used for continuous variables. Statistically significant variables were incorporated into a multivariate analysis. The multivariate analysis allows for an evaluation of the influence of blood transfusion on recurrence while controlling for variables found to be significant using univariate analysis.

A total of 269 patients with SCCHN treated surgically at Stanford University Medical Center during the study period were identified. Patients excluded from the study included 48 patients with in situ and stage I SCCHN, 15 patients without evidence of recurrent disease who died before 2 years of follow-up, 3 patients with distant metastases at the time of surgery, 2 patients with synchronous primary tumors, 28 patients with insufficient (<2-year) follow-up, and 8 patients with incomplete medical records. One hundred sixty-five patients met the study criteria.

Of these, 60 patients received blood products. A total of 28 autologous blood recipients were identified; 10 of these patients received both autologous and heterologous blood and therefore were placed in the heterologous transfusion group. The mean patient age was 59.3 years, and 70% of the patients were men. Thirty-five patients had stage II SCCHN; 34 had stage III; 77 had stage IV; and the stage for 19 patients was unavailable.

The incidence of transfusion with respect to the variables studied is shown in Table 1. The autologous and heterologous transfusion groups had a higher percentage of patients with previous treatment of the current malignancy (P=.01), higher volume of surgical blood loss (P<.001), and lower preoperative hematocrit values (P<.001) than those not undergoing transfusion; there were no statistically significant differences between the autologous and heterologous transfusion groups, although there was a trend toward a higher rate of lymph node metastases (P=.22) and positive margins (P=.33) in the heterologous group.

Table Graphic Jump LocationTable 1. Distribution of Variables by Transfusion Group

The results of the univariate analysis of nominal variables is summarized in Table 2. Previous treatment of the current malignancy (P<.001), heterologous blood transfusion (P=.006), margin status (P=.01), and the presence of nodal metastases (P=.02) were significantly associated with recurrence. Receipt of autologous blood was not associated with an increased recurrence rate. Univariate analysis of the continuous variables included preoperative hematocrit value (P=.19) and age (P=.14); estimated blood loss (P=.01) had a statistically significant association with recurrence. The overall recurrence rate was 41%. Patients in the heterologous group had a 59% recurrence rate, whereas those who received autologous blood or no transfusion had recurrence rates of 33% and 35%, respectively. The percentage of patients without recurrence during 24 months of follow-up is shown for each transfusion group in Figure 1.

Table Graphic Jump LocationTable 2. Summary of the Univariate Analysis of Nominal Variables
Place holder to copy figure label and caption

The percentage of patients without recurrence in each transfusion group is shown during the 24 months of follow-up.

Graphic Jump Location

Patients in the autologous group received a mean of 1.2 U of blood, whereas those in the heterologous group received a mean of 2.9 U. In the heterologous group, 2 patients received 2 U of fresh frozen plasma; otherwise, all blood products were packed red blood cells or whole blood. As heterologous blood transfusion was associated with an increased risk for recurrence, the effect of the quantity of heterologous blood received was examined. The recurrence rates of patients who received different amounts of heterologous blood is summarized in Table 3. The number of units of heterologous blood received was not significantly associated with risk for recurrence by univariate analysis (P=.58).

Table Graphic Jump LocationTable 3. Analysis of Recurrence by Units of Heterologous Blood

Multivariate analysis with the Cox semiparametric regression model was initially constructed using the 3 transfusion groups. The β coefficient, a measure of the correlation between the variable of interest and recurrence, was used to calculate an adjusted odds ratio. The adjusted odds ratio associated with receipt of heterologous blood was 1.40 (40% increase in relative risk). Statistically significant variables were then added to the model, and the results are summarized in Table 4. In this model, the risk associated with previous treatment of the current malignancy, nodal disease, positive margin, and receipt of heterologous blood remained statistically significant.

Table Graphic Jump LocationTable 4. Multivariate Analysis of Variables That Were Statistically Significant by Univariate Analysis*

Although it is generally accepted that heterologous blood transfusion causes immunosuppression, it is not clear whether perioperative blood transfusion in patients with cancer causes increased recurrence rates. The otolaryngology literature is divided as to whether heterologous blood exerts an independent effect on recurrence. One problem with some of the earlier studies in this field was that patient variables that could effect recurrence were not controlled.5,8,9 Nine studies included a multivariate analysis6,7,1016; 4 found heterologous blood transfusion to be a significant risk factor independent of other variables. Woolley et al,11 in addition to reviewing their own experience, performed a meta-analysis of 5 of the published studies and found that transfusion was significantly associated with recurrence. In our study, heterologous transfusion incurred a statistically significant increased relative risk using multivariate analysis compared with autologous or no transfusion.

The data analysis of our 165 patients also revealed that previous treatment of the current malignancy, positive margins, and presence of nodal metastases were significantly associated with recurrence using multivariate analysis. Of our 165 patients, 32% had a history of failed initial treatment, which in most cases was radiotherapy but also included surgery, chemotherapy, or both. This failure of previous treatment may indicate that the patient has a phenotypically more aggressive tumor or has a weakened immune system. The patients with positive margins fared the worst, with a recurrence rate of 65%, whereas nodal metastases were associated with a 53% recurrence rate. When these 3 powerful variables were controlled, the increased relative risk associated with heterologous blood transfusion remained statistically significant.

Our results suggest that a number of variables tend to be associated with the need for blood transfusion. Patients undergoing transfusion had a larger percentage of the following variables: previous treatment of the current malignancy, higher volume of surgical blood loss, and lower preoperative hematocrit values. Despite this distribution of variables, the rate of recurrence was almost identical between patients who received autologous transfusions and those who received no transfusion.

Patients in the heterologous transfusion group differed from patients in the autologous transfusion group in that they had a higher incidence of positive margins and lymph node metastases. The higher frequency of these variables in patients who require heterologous blood transfusions may denote the presence of more advanced tumors, which sometimes resulted in the inability of patients to donate their own blood. Controlling for margins and node status, the receipt of heterologous blood still incurred a significant independent risk.

Patients with recurrent nasopharyngeal carcinoma treated with a transpalatal nasopharyngectomy were included in our study. This subgroup of 13 patients accounted for a relatively high percentage (28%) of the autologous blood transfusions (Table 1). This may reflect a group of patients in whom blood loss was successfully anticipated (62% of patients required a blood transfusion), and, therefore, autologous blood was more consistently obtained. The recurrence rate in the group of patients with nasopharyngeal carcinoma was 46%, the second highest recurrence rate by location (Table 2). Despite having a larger proportion of patients with nasopharyngeal carcinoma, the recurrence rates of patients receiving autologous blood were nearly identical to those who did not receive a transfusion.

Although a number of studies have reviewed outcome following heterologous transfusion in head and neck cancer surgery, none have examined the influence of autologous blood products. There are few data in other surgical disciplines examining the relationship of recurrence with heterologous and autologous blood transfusion. Ness et al19 performed a prospective study of 309 patients treated with radical surgery for prostate cancer and found that recurrence rates did not differ significantly between patients who received heterologous blood compared with those who received autologous blood or no transfusion. Busch et al20 prospectively evaluated 475 cases of colorectal cancer and found no significant difference in recurrence rates of patients who had autologous or heterologous perioperative blood transfusions; however, transfusion with either blood product carried a much higher risk than no transfusion.

Autologous blood transfusion traditionally has been assumed to be free of most risks associated with heterologous transfusion. Recently, several investigators have cautioned against this assumption, hypothesizing that autologous blood may have an impact on cancer recurrence via immunosuppressive actions.17,18 Vliet et al21 reported that blood processing and storage resulted in changes that inhibited the proliferation response of lymphocytes. Whether such changes effect cancer recurrence rates is not known. In animals, syngeneic transfusions have not been shown to have the adverse effects on malignant disease seen with allogeneic transfusion.22,23 The results of our study suggest that perioperative autologous blood transfusion is not associated with increased recurrence rates.

Evidence that heterologous blood has immunosuppressive properties is much stronger than that described for autologous blood, yet the mechanism remains poorly understood. A number of changes in immune profile have been reported in patients who received allogeneic blood transfusions, including an increased level of CD8 suppressor cells,24 decreased levels of CD4 helper cells and interleukin 2 receptor–positive helper cells,25 and a decreased level of natural killer cells.26 It had been presumed that the cellular components of transfused blood were responsible for these immune modifications. More recently, however, transfusion of plasma has also been found to be associated with immunosuppression.27,28 The details of transfusion-induced immunosuppression remain to be better elucidated.

Our results demonstrate an independent risk associated with heterologous transfusion that was statistically significant using multivariate analysis. The increased relative risk is worrisome and warrants judicious use of heterologous blood products. Transfusion with autologous blood not only protects patients from the risk for blood-borne infection and transfusion reaction, but it may also diminish the risk for increased recurrence frequently associated with heterologous blood transfusion. Our results suggest that autologous blood transfusion carries the same risk as no transfusion. Preoperative autologous blood collection for head and neck surgery is therefore justified, and autologous blood products should be used if possible when transfusion is necessary.

Accepted for publication January 11, 1999.

Presented in part at the Western Section Meeting of the American Laryngological, Rhinological and Otological Society, Scottsdale, Ariz, January 14, 1995.

Reprints: David J. Terris, MD, Room R135, Edwards Building, Stanford University Medical Center, Stanford, CA 94305-5328 (e-mail: dterris@stanford.edu).

Opelz  GSengar  DPSMickey  MRTerasaki  PI Effect of blood transfusions on subsequent kidney transplants. Transplant Proc. 1973;5253- 259
Gantt  CL Red cells for cancer patients [letter]. Lancet. 1981;2363
Vamrakis  EMoore  SB Perioperative blood transfusion and colorectal cancer recurrence: a qualitative statistical overview and meta-analysis. Transfusion. 1993;33754- 765
Eickhoff  JHAndersen  JLaybourn  C Perioperative blood transfusion does not promote recurrence and death after mastectomy for breast cancer: the Danish Breast Cancer Cooperative Group. Br J Surg. 1991;781358- 1361
Bock  MGrevers  GKoblitz  MHeim  MUMempel  S Influence of blood transfusion on recurrence, survival and postoperative infections of laryngeal cancer. Acta Otolaryngol (Stockh). 1990;110155- 160
Von Doersten  PCruz  RMSelby  JHilsinger  RL Transfusion, recurrence, and infection in head and neck cancer surgery. Otolaryngol Head Neck Surg. 1992;10660- 67
Schuller  DEScott  CWilson  KM  et al.  The effect of perioperative blood transfusion on survival in head and neck cancer. Arch Otolaryngol Head Neck Surg. 1994;120711- 716
Johnson  JTTaylor  FHThearle  PB Blood transfusion and outcome in stage III head and neck carcinoma. Arch Otolaryngol Head Neck Surg. 1987;113307- 310
Jackson  RMRice  DH Blood transfusions and recurrence in head and neck cancer. Ann Otol Rhinol Laryngol. 1989;98171- 173
Jones  KRWeissler  MC Blood transfusion and other risk factors for recurrence of cancer of the head and neck. Arch Otolaryngol Head Neck Surg. 1990;116304- 309
Woolley  ALHogikyan  NDGates  GAHaughey  BHSchechtman  KBGoldenberg  JL The effect of blood transfusion upon recurrence of head and neck carcinoma: retrospective review and meta-analysis. Ann Otol Rhinol Laryngol. 1992;109724- 730
Ell  SRStell  PM Blood transfusion and survival after laryngectomy for laryngeal carcinoma. J Laryngol Otol. 1991;105293- 294
Alun-Jones  TClarke  PJMorrissey  S  et al.  Blood transfusion and laryngeal cancer. Clin Otolaryngol. 1991;16240- 244
Barra  SBarzan  LMaione  A  et al.  Blood transfusion and other prognostic variables in the survival of patients with cancer of the head and neck. Laryngoscope. 1994;10495- 98
McCulloch  TMVanDaele  DJHillel  A Department of Veterans Affairs Laryngeal Cancer Study Group: blood transfusion as a risk factor for death in stage III and IV operative laryngeal cancer. Arch Otolaryngol Head Neck Surg. 1995;1211227- 1235
Sturgis  EMCongdon  DJMather  FJMiller  RH Perioperative transfusion, postoperative infection, and recurrence of head and neck cancer. South Med J. 1997;901217- 1224
Ross  WB Blood transfusions and prognosis in colorectal cancer. N Engl J Med. 1994;3291354- 1355
Blumberg  NHeal  JM Effects of transfusion on immune function: cancer recurrence and infection. Arch Pathol Lab Med. 1994;118371- 379
Ness  PMWalsh  PCZahurak  MBaldwin  MLPiantadosi  S Prostate cancer recurrence in radical surgery patients receiving autologous or homologous blood. Transfusion. 1992;3231- 36
Busch  ORHop  WCHoynck van Papendrecht  MAWMarquet  RLJeekel  J Blood transfusions and prognosis in colorectal cancer. N Engl J Med. 1993;3281372- 1376
Vliet  WCDock  NLDavey  FR Factors in the liquid portion of stored blood inhibit the proliferative response in mixed lymphocyte cultures. Transfusion. 1989;2941- 45
Singh  SKMarquet  RLde Bruin  RWFWestbroek  DLJeekel  J Promotion of tumor growth by blood transfusions. Transplant Proc. 1987;191473- 1474
Waymack  JPChance  WT Effect of blood transfusions on immune function, IV: effect on tumor growth. J Surg Oncol. 1988;39159- 164
Gafter  UKalechman  YSrendni  B Induction of a subpopulation of suppressor cells by a single blood transfusion. Kidney Int. 1992;41143- 148
MacRae  JDLampe  HBanerjee  D Blood transfusions and phenotypic immune profile in head and neck cancer patients undergoing surgical resection. J Otolaryngol. 1991;20310- 314
Triulzi  DJVanek  KRyan  DHBlumberg  N A clinical and immunologic study of blood transfusion and postoperative bacterial infection in spinal surgery. Transfusion. 1992;32517- 524
Blumberg  NHeal  JM Evidence for plasma-mediated immunomodulation: transfusions of plasma-rich blood components are associated with a greater risk of acquired immunodeficiency syndrome than transfusions of red cells alone. Transplant Proc. 1988;201138- 1142
Marsh  JDonnan  PTHamer-Hodges  DW Association between transfusion with plasma and the recurrence of colorectal carcinoma. Br J Surg. 1990;7623- 626

Figures

Place holder to copy figure label and caption

The percentage of patients without recurrence in each transfusion group is shown during the 24 months of follow-up.

Graphic Jump Location

Tables

Table Graphic Jump LocationTable 1. Distribution of Variables by Transfusion Group
Table Graphic Jump LocationTable 2. Summary of the Univariate Analysis of Nominal Variables
Table Graphic Jump LocationTable 3. Analysis of Recurrence by Units of Heterologous Blood
Table Graphic Jump LocationTable 4. Multivariate Analysis of Variables That Were Statistically Significant by Univariate Analysis*

References

Opelz  GSengar  DPSMickey  MRTerasaki  PI Effect of blood transfusions on subsequent kidney transplants. Transplant Proc. 1973;5253- 259
Gantt  CL Red cells for cancer patients [letter]. Lancet. 1981;2363
Vamrakis  EMoore  SB Perioperative blood transfusion and colorectal cancer recurrence: a qualitative statistical overview and meta-analysis. Transfusion. 1993;33754- 765
Eickhoff  JHAndersen  JLaybourn  C Perioperative blood transfusion does not promote recurrence and death after mastectomy for breast cancer: the Danish Breast Cancer Cooperative Group. Br J Surg. 1991;781358- 1361
Bock  MGrevers  GKoblitz  MHeim  MUMempel  S Influence of blood transfusion on recurrence, survival and postoperative infections of laryngeal cancer. Acta Otolaryngol (Stockh). 1990;110155- 160
Von Doersten  PCruz  RMSelby  JHilsinger  RL Transfusion, recurrence, and infection in head and neck cancer surgery. Otolaryngol Head Neck Surg. 1992;10660- 67
Schuller  DEScott  CWilson  KM  et al.  The effect of perioperative blood transfusion on survival in head and neck cancer. Arch Otolaryngol Head Neck Surg. 1994;120711- 716
Johnson  JTTaylor  FHThearle  PB Blood transfusion and outcome in stage III head and neck carcinoma. Arch Otolaryngol Head Neck Surg. 1987;113307- 310
Jackson  RMRice  DH Blood transfusions and recurrence in head and neck cancer. Ann Otol Rhinol Laryngol. 1989;98171- 173
Jones  KRWeissler  MC Blood transfusion and other risk factors for recurrence of cancer of the head and neck. Arch Otolaryngol Head Neck Surg. 1990;116304- 309
Woolley  ALHogikyan  NDGates  GAHaughey  BHSchechtman  KBGoldenberg  JL The effect of blood transfusion upon recurrence of head and neck carcinoma: retrospective review and meta-analysis. Ann Otol Rhinol Laryngol. 1992;109724- 730
Ell  SRStell  PM Blood transfusion and survival after laryngectomy for laryngeal carcinoma. J Laryngol Otol. 1991;105293- 294
Alun-Jones  TClarke  PJMorrissey  S  et al.  Blood transfusion and laryngeal cancer. Clin Otolaryngol. 1991;16240- 244
Barra  SBarzan  LMaione  A  et al.  Blood transfusion and other prognostic variables in the survival of patients with cancer of the head and neck. Laryngoscope. 1994;10495- 98
McCulloch  TMVanDaele  DJHillel  A Department of Veterans Affairs Laryngeal Cancer Study Group: blood transfusion as a risk factor for death in stage III and IV operative laryngeal cancer. Arch Otolaryngol Head Neck Surg. 1995;1211227- 1235
Sturgis  EMCongdon  DJMather  FJMiller  RH Perioperative transfusion, postoperative infection, and recurrence of head and neck cancer. South Med J. 1997;901217- 1224
Ross  WB Blood transfusions and prognosis in colorectal cancer. N Engl J Med. 1994;3291354- 1355
Blumberg  NHeal  JM Effects of transfusion on immune function: cancer recurrence and infection. Arch Pathol Lab Med. 1994;118371- 379
Ness  PMWalsh  PCZahurak  MBaldwin  MLPiantadosi  S Prostate cancer recurrence in radical surgery patients receiving autologous or homologous blood. Transfusion. 1992;3231- 36
Busch  ORHop  WCHoynck van Papendrecht  MAWMarquet  RLJeekel  J Blood transfusions and prognosis in colorectal cancer. N Engl J Med. 1993;3281372- 1376
Vliet  WCDock  NLDavey  FR Factors in the liquid portion of stored blood inhibit the proliferative response in mixed lymphocyte cultures. Transfusion. 1989;2941- 45
Singh  SKMarquet  RLde Bruin  RWFWestbroek  DLJeekel  J Promotion of tumor growth by blood transfusions. Transplant Proc. 1987;191473- 1474
Waymack  JPChance  WT Effect of blood transfusions on immune function, IV: effect on tumor growth. J Surg Oncol. 1988;39159- 164
Gafter  UKalechman  YSrendni  B Induction of a subpopulation of suppressor cells by a single blood transfusion. Kidney Int. 1992;41143- 148
MacRae  JDLampe  HBanerjee  D Blood transfusions and phenotypic immune profile in head and neck cancer patients undergoing surgical resection. J Otolaryngol. 1991;20310- 314
Triulzi  DJVanek  KRyan  DHBlumberg  N A clinical and immunologic study of blood transfusion and postoperative bacterial infection in spinal surgery. Transfusion. 1992;32517- 524
Blumberg  NHeal  JM Evidence for plasma-mediated immunomodulation: transfusions of plasma-rich blood components are associated with a greater risk of acquired immunodeficiency syndrome than transfusions of red cells alone. Transplant Proc. 1988;201138- 1142
Marsh  JDonnan  PTHamer-Hodges  DW Association between transfusion with plasma and the recurrence of colorectal carcinoma. Br J Surg. 1990;7623- 626

Correspondence

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Topics