Faculty Bibliography

OBJECTIVES: Since its introduction in 1987, the Cox-maze procedure has been the gold standard for the surgical treatment of atrial fibrillation. At our institution, this procedure has evolved from the cut-and-sew technique (Cox-maze III procedure) to one using bipolar radiofrequency energy and cryoablation as ablative sources to replace most incisions (Cox-maze IV procedure). This study compared surgical outcomes of patients undergoing the Cox-maze III procedure versus those of patients undergoing the Cox-maze IV procedure by using propensity analysis. METHODS: From April 1992 through July 2005, 242 patients underwent the Cox-maze procedure for atrial fibrillation. Of these, 154 patients had the Cox-maze III procedure, and 88 had the Cox-maze IV procedure. Logistic regression analysis was used to identify covariates among 7 baseline patient variables. Using the significant regression coefficients, each patient's propensity score was calculated, allowing selectively matched subgroups of 58 patients each. Operative outcomes were analyzed for differences. Late follow-up was available for 112 (97%) patients. Freedom from atrial fibrillation recurrence and survival was calculated at 1 year by using Kaplan-Meier analysis. RESULTS: The Cox-maze III procedure had significantly longer crossclamp times. There was no significant difference in intensive care unit and hospital stay, 30-day mortality, permanent pacemaker placement, early atrial tachyarrhythmias, late stroke, and survival. Freedom from atrial fibrillation recurrence was greater than 90% in both groups at 1 year. CONCLUSIONS: The use of bipolar radiofrequency ablation has simplified the Cox-maze procedure, making it applicable to virtually all patients with atrial fibrillation undergoing concomitant cardiac surgery. The Cox-maze IV procedure produces similar surgical outcomes to the Cox-maze III procedure at 1 year of follow-up.

OBJECTIVE: Patients with severe left ventricular (LV) dysfunction have a poor long term survival despite complete surgical revascularization. Recent data suggests that the use of Implantable Cardioverter-Defibrillator (ICD) improves survival in patients with severe LV dysfunction. We compared the survival impact of ICD implantation in patients with severe LV dysfunction who underwent CABG. METHODS: Between January 1996 and August 2004, 305 patients with LV ejection fraction (EF) < or = 25% had CABG surgery at our institution. Demographics of patients who had received an ICD (ICD+) in the post -operative period was compared to those without ICD (ICD-). Survival was evaluated by the Kaplan-Meier method. RESULTS: Of the entire group, 35 (11.5%) patients received an ICD with a median of 2 (+/-2) years after CABG. Indication for ICD implantation was clinical evidence of non sustained ventricular tachycardia (NSVT). There were no differences between the 2 groups with respect to age, gender, NYHA classification, number of bypasses, or other co-morbidities. Survival at 1, 3 and 5 years was 88%, 79%, and 67% for the ICD- group compared to 94%, 89% and 83% for the ICD+ group, respectively (figure, p < 0.05). CONCLUSION: Implantation of ICD after CABG confers improved short and long term survival benefit to patients with severe LV dysfunction. Prophylactic ICD implantation in the setting of severe LV dysfunction and CABG surgery should be considered.

BACKGROUND: Infective endocarditis is associated with a high rate of long-term mortality. Patients with a history of intravenous drug use (IVDU) are at increased risk for infective endocarditis. However, few studies have reported results of surgical treatment on this population. We present 19.5 years of experience with surgically treated patients with infective endocarditis. METHODS: A retrospective study of all cardiac surgeries with a diagnosis of infective endocarditis at a single institution from 1986 to 2005 was performed. Logistic stepwise regression with an end point of operative mortality was done. Variables were age, gender, race, history of drug use, previous valve surgery, and previous valve replacement. Perioperative and outcome variables were compared between IVDU and non-IVDU populations. RESULTS: The IVDU population required surgery at a younger age (39 +/- 9 years versus 54 +/- 15 years; p < 0.001). Overall operative mortality was 12% (41/346). The perioperative complication rate was similar for both groups. When adjusted for age, the two groups had similar long-term survival (p = 0.78). Kaplan-Meier estimator showed that survival at 10 and 15 years was 66% and 54% for IVDU and 56% and 42% for non-IVDU (number at risk, 19, 11, and 61, 28, respectively; p = 0.137). Reoperation for recurrent infective endocarditis was necessary in 9 (17%) of 52 of the IVDU group versus 14 (5%) of 270 of the non-IVDU group (p = 0.03). CONCLUSIONS: Patients with a history of IVDU required reoperation for recurrent infective endocarditis at a significantly higher rate than the non-IVDU patients. Long-term survival was similar between the younger IVDU population and the older non-IVDU population. Anticipated life span is one of many factors when considering prosthetic valve choice in this population.

BACKGROUND: Recombinant BNP (nesiritide) is known to reduce endothelin levels, cause afferent arteriole vasodilation, and increase natriuresis and diuresis. We hypothesized that intraoperative infusion of BNP may benefit renal function in cardiac transplant patients. METHODS: From June 2003 to September 2005, 22 consecutive heart transplant patients received BNP at a dose of 0.01 microg/kg/min before initiation of cardiopulmonary bypass (group A). BNP infusion was continued for a mean of 3.3 +/- 1.9 days. Hemodynamics, urine output, and serum creatinine levels were prospectively collected and compared with 22 consecutive patients who underwent heart transplantation between May 2002 and June 2003 following the identical transplant protocol, but without BNP infusion (group B). RESULTS: At 24 hours postoperatively, mean blood pressure was comparable between groups (87 +/- 11 mm Hg vs 89 +/- 17 mm Hg, P = .7), but pulmonary artery pressure (18 +/- 5 mm Hg vs 24 +/- 5 mm Hg, P = .001) and central venous pressure (12 +/- 5 mm Hg vs 16 +/- 4 mm Hg, P = .01) were lower with BNP infusion, whereas cardiac index was augmented (2.8 +/- 0.5 vs 2.4 +/- 0.6, P = .03). Requirement of low-dose inotropic and vasopressor support was equally distributed between groups (P > or = .72). Postoperative urine output for the initial 24 hours was higher in group A (84 +/- 15 vs 55 +/- 36 mL/h, P = .01). None of the patients with BNP infusion required additional diuretics or renal replacement therapy during the first week after transplantation. Mean postoperative serum creatinine levels as compared with preoperative values remained unchanged within group A (P = .12), but increased significantly in group B (P < .001). CONCLUSIONS: Intraoperative BNP infusion in heart transplant recipients was associated with favorable postoperative hemodynamics, significantly improved urine output, and stable serum creatinine levels. A prospective, randomized, multicenter trial is warranted to evaluate the potential renal protective benefits of intraoperative BNP infusion in this patient population.

BACKGROUND/OBJECTIVE: While the Cox-Maze procedure remains the gold standard for the surgical treatment of atrial fibrillation (AF), the use of ablation technology has revolutionized the field. To simplify the procedure, our group has replaced most of the incisions with bipolar radiofrequency ablation lines. The purpose of this study was to examine results using bipolar radiofrequency in 130 patients undergoing a full Cox-Maze procedure, a limited Cox-Maze procedure, or pulmonary vein isolation alone. METHODS: A retrospective review was performed of patients who underwent a Cox-Maze procedure (n = 100), utilizing bipolar radiofrequency ablation, a limited Cox-Maze procedure (n = 7), or pulmonary vein isolation alone (n = 23). Follow-up was available on 129 of 130 patients (99%). RESULTS: Pulmonary vein isolation was confirmed by intraoperative pacing in all patients. Cross-clamp time in the lone Cox-Maze procedure patients was 44 +/- 21 minutes, and 104 +/- 42 minutes for the Cox-Maze procedure with a concomitant procedure, which was shortened considerably from our traditional cut-and-sew Cox-Maze procedure times (P < 0.05). There were 4 postoperative deaths in the Cox-Maze procedure group and 1 in the pulmonary vein isolation group. The mean follow-up was 13 +/- 10, 23 +/- 15, and 9 +/- 10 months for the Cox-Maze IV, the pulmonary vein isolation, and the limited Cox-Maze procedure groups, respectively. At last follow-up, freedom from AF was 90% (85 of 94), 86% (6 of 7), and 59% (10 of 17) in the in the Cox-Maze procedure group, limited Cox-Maze procedure group, and pulmonary vein isolation alone group, respectively. CONCLUSIONS: The use of bipolar radiofrequency ablation to replace Cox-Maze incisions was safe and effective at controlling AF. Pulmonary vein isolation alone was much less effective, and should be used cautiously in this population.

BACKGROUND: Severe aortic insufficiency (AI) with preserved left ventricular (LV) function may be associated with a long asymptomatic period and unpredictable course on medical therapy. Since myocardial wall stress is closely related to both pathologic cardiac remodeling and ultimately to LV decompensation, a more accurate description of regional wall stress may improve our ability to appropriately manage these patients. The objective of this study was to define differences in instantaneous global and regional three-dimensional end-systolic maximum principal stress (ESS) between normal patients and patients with AI, both before and after aortic valve replacement (AVR) using magnetic resonance imaging (MRI) and finite element analysis (FEA). METHODS: Magnetic resonance imaging was performed on 20 normal volunteers and 14 patients with moderate to severe AI with normal systolic function (ejection fraction: 57 +/- 0.6) before and after AVR. Finite element analysis was utilized to estimate global and regional ESS. RESULTS: Both global (p < 0.001) and regional (p < 0.001 in all segments) ESS were significantly higher in the preoperative AI patients when compared with their postoperative values and normal controls. Postoperative ESS was significantly lower than the normal controls (p = 0.002). CONCLUSIONS: Three-dimensional regional and global end-systolic LV wall stress can be determined by MRI and finite element analysis. Values of ESS in patients with chronic AI were elevated prior to AVR and normalized after AVR. This method may have considerable potential as a noninvasive, clinically applicable index of regional LV geometry and function that may help with the serial evaluation of patients with AI.

BACKGROUND: Significant coronary artery disease (CAD) is an exclusion criterion for lung transplantation at most centers. However, the impact of preoperative noncritical CAD (single or multivessel mild <30% or moderate 30% to 50% stenosis) on the outcomes of lung transplantation is unknown. METHODS: A retrospective review of 268 adult patients who underwent lung transplantation between June 1998 and June 2003 at Barnes-Jewish Hospital, a tertiary care center affiliated with Washington University School of Medicine, was performed. RESULTS: Two hundred ten patients had coronary angiography performed as part of their pretransplantation evaluation. Among these patients, 177 patients had no CAD, and 33 patients (mild, 16; moderate, 17) had noncritical CAD. Patients with noncritical CAD were older (59 versus 55 years, p < 0.001) and had a higher prevalence of diabetes (24% versus 9%, p = 0.014) and systemic hypertension (58% versus 36%, p = 0.004) than patients without CAD. There was no significant difference in the underlying lung disease, other comorbidities, type of lung transplantation performed, early postoperative complications, and hospital or late mortality between recipients with or without CAD. Among the patients with noncritical CAD, there was no hospital mortality and no late cardiac mortality. Three recipients with preoperative moderate CAD developed late ischemic cardiac events, and revascularization was performed in 2 of these recipients. Long-term survival was similar among recipients with or without preoperative CAD. CONCLUSIONS: Preoperative noncritical (mild or moderate) CAD was not associated with increased perioperative morbidity or mortality, and it did not adversely affect short-term or long-term survival. Late ischemic events developed in 18% of the recipients with moderate CAD disease with no effect on mortality.