Faculty Bibliography

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.

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: 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: With recent improvements in medical and device therapy, the benefit of cardiac transplantation for UNOS Status 2 patients has been questioned. No randomized trial has been performed to compare transplantation versus contemporary medical therapy. METHODS: Between January 1996 and December 2003, 203 patients were listed at our institution for heart transplantation as UNOS Status 2. We performed a retrospective review to determine outcomes in these patients. RESULTS: Demographics of this cohort revealed a mean age of 52 years, female sex in 28%, and ischemic etiology in 47%. Eighty-one patients (40%) had an implantable cardiac defibrillator. A total of 64 patients (32%) had to be upgraded in their UNOS status, with 9 requiring a left ventricular assist device. Of the entire group, 95 (47%) underwent transplantation at a mean time of 303 days, 45 (22%) died while waiting at a mean time of 397 days, and 24 (12%) were removed from the waiting list due to deterioration in medical condition such that transplantation was no longer an option. The remaining patients continue to wait or have been removed from consideration due to improved condition. Survival at 1- and 3-years postlisting was 94% and 87% for patients who received transplants compared to 81% and 57% for patients who did not receive transplants (P < .01). CONCLUSION: A significant number of patients listed as Status 2 are upgraded in UNOS status or die while on the waiting list. Early and midterm survival is significantly better with transplantation. Identification of variables associated with deterioration may allow for better risk stratification in the future. At this point, transplantation offers the best outcome

Reoperations during ventricular assist device (VAD) explantation and subsequent heart transplantation are difficult procedures because of dense adhesions, obliterated planes of dissection, and proximity of the right ventricle to the sternum. We present our approach for left VAD explantation to minimize potential complications that may occur during this procedure.

Despite advances in mechanical circulatory support, cardiogenic shock continues to have a high mortality. We reviewed our experience with pulsatile versus non-pulsatile temporary mechanical support at our institution to determine optimal strategy for survival. From January 2001 to December 2003, mechanical support for cardiogenic shock was instituted in 38 patients. Non-pulsatile devices (NP group) were used in 22 patients and pulsatile devices (P group) in 16 patients. Indications for the NP group were post-cardiotomy shock (PCS) in 17, myocardial infarction in 2, and isolated post-cardiotomy right ventricular failure in 3 patients. In the P group, 9 had the device placed for PCS, 3 for viral myocarditis, 1 after myocardial infarction, and 3 for right ventricular (RV) failure. Overall, bleeding, limb ischemia, and multi-system organ failure were higher in NP group with 5 weaned and 3 surviving to discharge (14%). In the P group, survivors included 7 weaned and 3 transplanted patients (63%). With the exception of isolated RV failure, we obtained a dismal survival result with ECMO/centrifugal circuits for treatment of cardiogenic shock. For refractory pump failure, improved survival was achieved by using intermediate-term pulsatile devices with early transition to a chronic device and/or heart transplantation.