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Ann Thorac Surg 2009;88:70-75. doi:10.1016/j.athoracsur.2009.04.022
© 2009 The Society of Thoracic Surgeons
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Original Articles: Adult Cardiac

The July Effect: Impact of the Beginning of the Academic Cycle on Cardiac Surgical Outcomes in a Cohort of 70,616 Patients

Faisal G. Bakaeen, MDa,b,c,*, Joseph Huh, MDa,b,c, Scott A. LeMaire, MDa,c, Joseph S. Coselli, MDa,c, Shubhada Sansgiry, PhDb, Prasad V. Atluri, MDb, Danny Chu, MDa,b,c

a Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas
b The Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas
c The Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas

Accepted for publication April 9, 2009.

* Address correspondence to Dr Bakaeen, Assistant Professor of Surgery, Department of Cardiothoracic Surgery, Michael E. DeBakey VAMC, OCL 112, 2002 Holcombe Blvd, Houston, TX 77030 (Email: fbakaeen{at}bcm.edu).


   Abstract
Top
 Abstract
Introduction
 Patients and Methods
 Results
 Comment
 Acknowledgments
 References
 
Background: Because surgical residents' level of experience may be at its nadir early in the academic year, academic seasonality—or the "July effect"—could affect cardiac surgical outcomes.

Methods: Prospectively collected data from the Department of Veterans Affairs Continuous Improvement in Cardiac Surgery Program were used to identify 70,616 consecutive cardiac surgical procedures performed between October 1997 and October 2007. Morbidity and mortality rates were compared between early (July 1 to August 31, n = 11,975) and late (September 1 to June 30, n = 58,641) periods in the academic year. A prediction model was constructed by using stepwise logistic regression modeling.

Results: The two patient groups had similar demographic and risk variables. Isolated coronary artery bypass grafting accounted for 76.7% of early-period procedures and 75.8% of later-period procedures (p = 0.03). Morbidity rates did not differ significantly between the early (14.0%) and later periods (14.2%; odds ratio [OR], 1.01; 95% confidence interval [CI], 0.96 to 1.07; p = 0.67) and operative mortality was similar, 3.7% vs 3.9% (OR, 0.99; 95% CI, 0.89 to 1.11; p = 0.90). The early portion of the year was associated with longer cardiac ischemia times (84 ± 40 vs 83 ± 42 minutes), cardiopulmonary bypass times (126 ±52 vs 124 ±56 minutes), and total surgical times (295 ± 90 vs 288 ± 90 minutes; p < 0.05 for all).

Conclusions: The early part of the academic year was associated with slightly longer operative times; however, risk-adjusted outcomes were similar in both periods. This finding should lessen concerns about the quality of cardiac surgical care at the beginning of the academic year.


   Introduction
Top
 Abstract
 Introduction
Patients and Methods
 Results
 Comment
 Acknowledgments
 References
 
The month of July marks the beginning of the academic year and is universally associated with an influx of new or junior residents. Therefore, the level of experience of front-line medical caregivers may not be as high in July as it is later in the academic year. In the academic surgical arena, the surgical and perioperative care skills of the residents are usually at their nadir at the beginning of the academic year. It is therefore logical to theorize that the characteristic cyclic rotation of residents may affect surgical outcomes.

In a recent landmark study, Englesbe and colleagues [1] used the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) to look at seasonal variations in surgical outcomes. The findings suggested a real seasonal discrepancy in outcomes: there was an 18% increase in risk-adjusted surgical morbidity and a 41% increase in risk-adjusted surgical mortality during the months of July and August compared with a later period in the academic year. In contrast, concerns about poor outcomes in the month of July were refuted in various other clinical milieus [2–4], including a recent large, nationwide study in the field of obstetrics [4].

Little is known about the effect of academic seasonality on cardiac surgical outcomes. Cardiac surgery involves complex and high-acuity procedures, which calls into question the validity of any extrapolations made from findings in other surgical specialties. A study from a single-center experience from the United Kingdom showed that periods of change in resident surgical staff were associated with increased risk-adjusted in-hospital mortality after complex cardiac operations [5]. At our hospital, we identified no adverse effect of resident turnover in July on cardiac surgical outcomes [6]. However, such findings may be institution-specific, and no generalized conclusions can be drawn from them. The purpose of this study was to use a large national database to identify any effect the beginning of the academic year might have on cardiac surgical outcomes.


   Patients and Methods
Top
 Abstract
 Introduction
 Patients and Methods
Results
 Comment
 Acknowledgments
 References
 
We obtained Institutional Review Board approval for the study and waiver of informed consent. We requested and received approval for the study from the Department of Veterans Affairs Surgical Quality Data Use Group (SQDUG).

Patients
The Veterans Affairs (VA) Continuous Improvement in Cardiac Surgery Program (CICSP) prospectively collects risk and outcomes data on all patients who undergo cardiac operations at any of 44 VA cardiac surgery centers [7–9]. Academic affiliation is one of the requirements for establishing a cardiac surgery program at a VA hospital. We conducted a telephone and electronic mailing survey of the 44 VA cardiac surgery programs, of which 40 (91%) responded and confirmed that medical/surgical trainees were involved in the care of cardiac surgical patients during the study period.

We received de-identified data for all patients who underwent open cardiac surgical procedures at the participating VA hospitals between October 1997 and October 2007. Next, we divided the patients into groups: 11,975 underwent an operation early in the academic year (July 1 to August 31), and 58,641 had a procedure later in the year (September 1 to June 30). Residents rotated at various times throughout the year at different centers, but the month of July universally marked the beginning of the academic year, and the choice of the periods that we evaluated was based on a local pilot study [6].

Outcomes
Two outcome variables were evaluated separately in this study: perioperative morbidity and 30-day operative mortality. CICSP defines 30-day operative mortality as the number of deaths that occur during the index hospitalization or within 30 days postoperatively, plus any deaths that occur more than 30 days postoperatively that are the direct result of a perioperative surgical complication. Perioperative morbidity is defined as the presence of any of the following major complications, alone or in combination: endocarditis, renal failure necessitating dialysis, mediastinitis, reoperation for bleeding, requiring a ventilator for longer than 48 hours, stroke, coma lasting longer than 24 hours, and any complication necessitating repeat cardiopulmonary bypass or mechanical circulatory support. This complication assessment uses standard definitions and criteria adopted by the VA Cardiac Surgery Consultants Board.

Statistical Analyses
The mean ± standard deviation was computed for continuous variables. After examining the parametric distributions, we used independent t tests to compare the parametric data collected during the early and later parts of the academic year. We used {chi}2 analyses to test for differences in categoric data.

Multivariable regression modeling was used to identify significant independent risk factors for perioperative morbidity and mortality. Variables used in the model included demographic, cardiac, and noncardiac risk factors. A prediction model was constructed by using stepwise logistic regression modeling with a significance level of p = 0.05 for entry and selection. All statistical analyses were conducted with SAS v9.1 (SAS Institute, Inc, Cary, NC).


   Results
Top
 Abstract
 Introduction
 Patients and Methods
 Results
Comment
 Acknowledgments
 References
 
Patients
A total of 70,616 cardiac surgical procedures were performed between October 1997 and October 2007. Intergroup differences in patient risk factors (Table 1) were small, and most were statistically insignificant.


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  		Table 1 Patient Demographics and Characteristics by Portion of Academic Cycle
 
Operations
Of the procedures performed in the early and late parts of the academic year (Table 2), about three-quarters involved coronary artery bypass grafting (CABG). Compared with the later part of the academic year, the early portion of the year was associated with slightly longer myocardial ischemia times (84 ± 40 vs 83 ± 42 minutes), cardiopulmonary bypass times (126 ± 52 vs 124 ± 56 minutes), operative times (295 ± 90 vs 288 ± 90 minutes), and total operating room times (386 ± 101 vs 377 ± 102 minutes; p < 0.05 for all). There was also a slightly higher prevalence of emergency procedures in the later part of the academic year than in the earlier part of the year (3% vs 4%; p < 0.0001).


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  		Table 2 Type and Extent of Operation
 
Morbidity
There were no differences in the incidences of the major tracked complications between the early and later part of the academic year, except for a slightly higher incidence of perioperative myocardial infarction in the later part of the year (Table 3). The overall unadjusted postoperative morbidity rate was 14.0% for the early part and 14.2% for the later part of the academic year (p = 0.6). The mean hospital length of stay was slightly longer in the later part of the academic year than in the earlier part (10.6 ± 14.5 vs 10.2 ± 13.0 days; p = 0.009).


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  		Table 3 Surgical Outcomes
 
Multivariable logistic regression, performed to control for potential confounding variables, associated several variables with postoperative morbidity (Table 4); however, the early period of the academic year was not one of them (odds ratio [OR], 1.01; 95% confidence interval [CI], 0.96 to 1.07; p = 0.67).


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  		Table 4 Risk Factors Significantly Associated with Morbidity and Mortality
 
Mortality
The (unadjusted) operative mortality rate was 3.7% for the early part and 3.9% for the later part of the academic year (p = 0.38). Multivariable logistic regression was performed to control for potential confounding variables; the early period of the academic year was not associated with operative mortality (OR, 0.99; 95% CI, 0.89 to 1.11; p = 0.90), although several other variables were (Table 4).

Subgroup Analyses
The (unadjusted) operative mortality rate for isolated CABG operations was 2.8% for the early part and 2.8% for the later part of the academic year (p = 0.99). When multivariable logistic regression was performed to control for potential confounding variables, the early period of the academic year was not associated with operative mortality (OR, 1.03; 95% CI, 0.89 to 1.18; p = 0.73).

The (unadjusted) operative mortality rate for cardiac surgical procedures other than CABG was 6.8% for the early part and 7.3% for the later part of the academic year (p = 0.35). When multivariable logistic regression was performed to control for potential confounding variables, the early period of the academic year was not associated with operative mortality (OR, 0.96; 95% CI, 0.81 to 1.13; p = 0.60).


   Comment
Top
 Abstract
 Introduction
 Patients and Methods
 Results
 Comment
Acknowledgments
 References
 
Although the "July effect" may influence outcomes in certain surgical settings, our findings do not support an association between the early part of the academic year and worse outcomes in cardiac surgery.

There are three stages of patient care at which residents can influence outcomes:

• In the preoperative stage, patient selection and preparation for the operation are important steps in optimizing outcomes.
• In the intraoperative stage, the complex nature of cardiac procedures amplifies the effects of any technical inadequacies or imperfections of the novice trainee; hence, an intraoperative error or suboptimal surgical performance can lead to detrimental outcomes.
• In the postoperative stage, minor lapses in vigilance or care delivery can translate into serious morbidity or mortality. In contrast, a vigilant resident is a valuable asset that can contribute positively to the care of patients.

Our group and others have demonstrated the safety of training residents to perform cardiac surgical procedures [10–17]. Cardiac surgical trainees' operative and perfusion times are inversely proportional to the trainees' level of surgical experience [11, 12]. Therefore, as expected, despite the similarities in the patients' risk profiles and the surgical case mix between the early and late time periods, the operative and perfusion times were slightly longer at the beginning of the academic year than they were later in the year. This slowdown may reflect a decline in the efficiency of surgical care delivery due to the disruptive effect of staff changeover. However, these longer operative times—even though significant from a statistical perspective in a large patient cohort such as the one at hand—did not translate into adverse outcomes. From a practical standpoint, the differences in both ischemia and perfusion times between the two periods were very small (≤2 minutes) and had no significant clinical implications.

Indeed, risk-adjusted morbidity and mortality rates for all cardiac surgical procedures were similar in the earlier and later parts of the academic year. This result agrees with our previously reported findings at a local institutional level [6]. Shuhaiber and colleagues [5] found no effect of cardiothoracic resident turnover on mortality rates after isolated CABG but detected an increase in risk-adjusted mortality after more complex cardiac cases that coincided with the periods of resident change. In the present national study, our subgroup analysis did not show any effect of the beginning of the academic year on the outcomes of isolated CABG or other cardiac procedures. Our negative finding verifies that our system of training young surgeons to do complicated and risky operations is sound and protects all patients from potential adverse events related to the educational process. This is a reassuring finding that the cardiac surgical specialty will have to maintain as it incorporates new procedures and technologies.

From a faculty standpoint, this era of intense public scrutiny has created tremendous pressure to achieve superior outcomes. In addition, hospital administrators and payers are constantly demanding an increase in efficiency and cuts in cost. Also, academic centers are faced with the challenge of training residents and delegating responsibility without compromising patient safety. Yet the responsibility of training the next generation of cardiac surgeons may pose at least a theoretic risk of compromising outcomes, because cardiothoracic surgery is a highly technical field in which hands-on experience is essential.

We believe that the key to achieving good results that are not influenced by resident turnover is close supervision and guidance by more senior members of the team, which is headed by faculty members. Such measures can help offset any deficiencies related to the inexperience of the new resident. In addition, it may be that more robust systems of care, resistant to the effects of the academic cycle, are used in cardiac surgery because of the complexity of the procedures involved and the morbidity burden of the patient population.

The care of cardiac patients involves more than one clinical service or specialty. Therefore, maintaining a reliable and predictable mode of care usually requires a multidisciplinary team approach and continuity of care that is not operator-dependent and that has built-in checks and safeguards. Such mechanisms are indeed vital to neutralizing any variability in care introduced by the staff changeovers that take place at various times. The staff heart surgeon, assisted by the more permanent auxiliary support staff, is at the center of a well-rehearsed process of care that is "July-proof."

Our study has several limitations. Because it is retrospective in nature, it is vulnerable to all the weaknesses and biases associated with such a design. Also, the study spanned a considerable period of time, during which changes occurred in surgical faculty, technology, and care delivery plans. Our data represent the experiences of many centers with different academic setups and timetables, and any resident changeovers that occurred after July were not adjusted for. Resident involvement in the cardiac care plan was verified in 91% of the centers our study examined; however, the level of training of residents and the extent of participation in the care process varied from one program to another.

The strengths of our study lie in its use of a large, robust, and validated prospective database and its use of risk-adjusted outcomes. Our study addresses a topic that has been inadequately evaluated: the relationship between the beginning of the academic timetable and cardiac surgical outcomes.

In conclusion, our findings show that cardiac surgical care delivery is as safe at the beginning of the academic cycle as it is later in the year. This should reassure patients about the quality of cardiac operations performed in the month of July.


   Acknowledgments
Top
 Abstract
 Introduction
 Patients and Methods
 Results
 Comment
 Acknowledgments
References
 
Stephen N. Palmer, PhD, ELS, contributed to the editing of this manuscript. The CICSP-X study was initially funded by VA Health Services Research and Development Grant #IHY 99214–1 (Dr Shroyer, Principal Investigator), with ongoing support from the Office of Patient Care Services, VA Central Office, Washington, DC. This project was supported in part by the Offices of Research and Development at the Northport and Eastern Colorado Health Care System Denver Veterans Affairs Medical Centers. Special acknowledgment is given to Randy Johnson, Lisa Schade, and Missy Bell, the team members responsible for the CICSP-X access to care report sections, working under the leadership of Dr Gerald McDonald (VA Central Office).


   References
Top
 Abstract
 Introduction
 Patients and Methods
 Results
 Comment
 Acknowledgments
 References
 

  1. Englesbe MJ, Pelletier SJ, Magee JC, et al. Seasonal variation in surgical outcomes as measured by the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) Ann Surg 2007;246:456-462.[Medline]
  2. Barry WA, Rosenthal GE. Is there a July phenomenon?. The effect of July admission on intensive care mortality and length of stay in teaching hospitals. J Gen Intern Med 2003;18:639-645.[Medline]
  3. Rich EC, Hillson SD, Dowd B, Morris N. Specialty differences in the ‘July phenomenon’ for Twin Cities teaching hospitals Med Care 1993;31:73-83.[Medline]
  4. Ford AA, Bateman BT, Simpson LL, Ratan RB. Nationwide data confirms absence of ‘July phenomenon’ in obstetrics: it's safe to deliver in July J Perinatol 2007;27:73-76.[Medline]
  5. Shuhaiber JH, Goldsmith K, Nashef SA. Impact of cardiothoracic resident turnover on mortality after cardiac surgery: a dynamic human factor Ann Thorac Surg 2008;86:123-130discussion 30–1.[Abstract/Free Full Text]
  6. Dhaliwal AS, Chu D, Deswal A, et al. The July effect and cardiac surgery: the effect of the beginning of the academic cycle on outcomes Am J Surg 2008;196:720-725.[Medline]
  7. Grover FL, Hammermeister KE, Burchfiel C. Initial report of the Veterans Administration Preoperative Risk Assessment Study for Cardiac Surgery Ann Thorac Surg 1990;50:12-26.[Abstract/Free Full Text]
  8. Grover FL, Johnson RR, Shroyer AL, Marshall G, Hammermeister KE. The Veterans Affairs Continuous Improvement in Cardiac Surgery Study Ann Thorac Surg 1994;58:1845-1851.[Abstract/Free Full Text]
  9. Grover FL, Shroyer AL, Hammermeister KE. Calculating risk and outcome: the Veterans Affairs database Ann Thorac Surg 1996;62:S6-S11.[Medline]
  10. Bakaeen FG, Dhaliwal AS, Chu D, et al. Does the level of experience of residents affect outcomes of coronary artery bypass surgery? Ann Thorac Surg 2009;87:1127-1133.[Abstract/Free Full Text]
  11. Haan CK, Milford-Beland S, O'Brien S, et al. Impact of residency status on perfusion times and outcomes for coronary artery bypass graft surgery Ann Thorac Surg 2007;83:2103-2110.[Abstract/Free Full Text]
  12. Goodwin AT, Birdi I, Ramesh TP, et al. Effect of surgical training on outcome and hospital costs in coronary surgery Heart 2001;85:454-457.[Abstract/Free Full Text]
  13. Roberts CS, Bocanegra NR. Comparison of the first 100 coronary bypass patients of a supervised resident with his first 100 as an attending surgeon at the same institution Am J Surg 1999;178:348-350.[Medline]
  14. Guo LR, Chu MW, Tong MZ, et al. Does the trainee's level of experience impact on patient safety and clinical outcomes in coronary artery bypass surgery? J Card Surg 2008;23:1-5.[Medline]
  15. Baskett RJ, Buth KJ, Legare JF, et al. Is it safe to train residents to perform cardiac surgery? Ann Thorac Surg 2002;74:1043-1048.[Abstract/Free Full Text]
  16. Sethi GK, Hammermeister KE, Oprian C, Henderson W. Impact of resident training on postoperative morbidity in patients undergoing single valve replacement. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. J Thorac Cardiovasc Surg 1991;101:1053-1059.[Abstract]
  17. Gulbins H, Pritisanac A, Ennker IC, Ennker J. Safety of a cardiac surgical training program over a twelve-year period Thorac Cardiovasc Surg 2007;55:494-499.[Medline]

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