Faculty Bibliography

Right ventricular dysfunction after myocardial infarction is associated with high morbidity and mortality. If optimal medical management is ineffective, early consideration should be given to right-sided temporary mechanical assistance.

OBJECTIVES: This study was undertaken to identify management strategies that maximize survival of patients with stage III non-small cell lung cancer and metachronous brain metastases and to determine whether any apparent improved survival was due to treatment or simply to patient selection. METHODS: Treatment evaluations of both primary non-small cell lung cancer and brain metastases were performed in 91 patients. Optimal treatment was identified by multivariable analysis. Propensity scoring and multivariable analysis were used to separate treatment benefit from patient selection. RESULTS: Risk-unadjusted median, 12-, and 24-month survivals were 5.2 months, 22%, and 10%, respectively. Younger age (P =.006), good performance status (P =.003), stage IIIA (P =.001), lung resection (P =.02), no other systemic metastases at time of diagnosis of brain metastases (P =.02), and either metastasectomy (P <.001) or stereotactic radiosurgery (P <.001) predicted best survival. However, metastasectomy or stereotactic radiosurgery was more common after lung resection (P =.02) and in patients with good performance status (P =.006), no other systemic metastases at time of diagnosis of brain metastases (P =.01), and fewer brain metastases (P <.001), suggesting that the patients with the best risk profile were selected for aggressive therapy of both lung primary and brain metastases. Despite this selection, analysis of propensity-matched patients demonstrated the benefit of lung resection and metastasectomy or stereotactic radiosurgery (P <.001). CONCLUSIONS: Younger patients with resected stage IIIA non-small cell lung cancer who have isolated metachronous brain metastases and good performance status do best when treated with metastasectomy or stereotactic radiosurgery. This survival benefit is a brain treatment effect, not the result of selecting the best patients for aggressive therapy.

BACKGROUND: Acute ischemic stroke after cardiac operations is a devastating complication with limited therapeutic options. As clinical trials of thrombolysis for acute ischemic stroke exclude patients with recent major surgery, the safety of intraarterial thrombolysis in this setting is unknown. METHODS: Thirteen patients with acute ischemic stroke within 12 days of cardiac operation underwent intraarterial thrombolysis within 6 hours of stroke symptom onset. The National Institutes of Health Stroke Scale was used to assess neurologic recovery. RESULTS: The mean age was 69 years (standard deviation +/-5 years) and 62% were men. Cardiac procedures included valve operations in 6 patients, coronary artery bypass grafting in 4, valve and coronary artery bypass grafting in 2, and left ventricular assist device in 1 patient. Atrial fibrillation occurred in 5 patients (38%). The mean time from operation to stroke was 4.3 days (standard deviation +/- 3 days). Thrombolysis was initiated within 3.6 hours (standard deviation +/-1.6 hours) of stroke symptom onset. Recanalization was complete in 1 patient, partial in 5, and 7 patients had low flow. Neurologic improvement occurred in 5 patients (38%). One patient needed a chest tube for hemothorax, 2 others were transfused for low hemoglobin. No operative intervention for bleeding was necessary. CONCLUSIONS: In select patients with acute ischemic stroke after recent cardiac operation, intraarterial thrombolysis appears to be reasonably safe and may lead to neurologic recovery.

OBJECTIVES: We sought to determine 5-year survival after extracorporeal membrane oxygenation for cardiac failure and its predictors, to assess survival and its predictors after bridging to transplantation or weaning from extracorporeal membrane oxygenation, and to identify factors influencing the likelihood of these outcomes. METHODS: Two hundred two adults (mean age, 55 +/- 14 years) were supported with extracorporeal membrane oxygenation between 1992 and July 1999 after cardiac failure. Follow-up extended to 7.5 years (mean, 3.8 +/- 2 years). Multivariable hazard function analysis identified predictors of survival, and logistic regression identified the determinants of bridging or weaning. RESULTS: Survival at 3 days, 30 days, and 5 years was 76%, 38%, and 24%, respectively. Patients surviving 30 days had a 63% 5-year survival. Risk factors (P <.1) included older age, reoperation, and thoracic aorta repair. Forty-eight patients were bridged to transplantation, and 71 were weaned with intent for survival. Survival was similar after either outcome (44% vs 40% 5-year survival, respectively). Failure to bridge or wean included (P <.03) renal and hepatic failure on extracorporeal membrane oxygenator support, occurrence of a neurologic event, and absence of infection. The dominant modes of death were cardiac failure and multisystem organ failure. CONCLUSIONS: Extracorporeal membrane oxygenation is versatile and salvages some patients who would otherwise die. Improvement in intermediate-term outcome will require a multidisciplinary approach to protect organ function and limit organ injury before and during this support.

Calculous cholecystitis severe enough to result in pyloric outlet obstruction is a rare occurrence. Impaction of a large calculus in the duodenum or stomach as a consequence of fistula formation is usually diagnosed on upper gastrointestinal series. Computed tomography is uncommonly used to diagnose this condition and was diagnostic in our patient.

Biologic grafts are the conduit of choice for vascular reconstructive procedures. The short-term thrombogenicity, patency, and stability of bovine arterial grafts, altered by a dye-mediated photo-oxidation process, was evaluated in the canine common femoral vein (CFV) and artery (CFA) model. Modified bovine interposition grafts were implanted in the CFV of 12 dogs and in the CFA of 11 dogs, respectively. Polytetrafluoroethylene (PTFE) implants on the contralateral side served as controls. Patency and histology were assessed at 1, 2, 4, and 6 weeks. In the CFV, patency of photo-oxidized grafts was 83% at 1 week and 71% at 2 weeks, compared to 17% and 0% for PTFE, respectively (p = 0.0033). In CFA, patency was 82% for the photo-oxidized graft and 63% for PTFE at 6 weeks (p = NS). Photo-oxidized grafts were nonreactive, without evidence of degenerative changes or cellular infiltration at all time periods. Compared to commercially available PTFE, photo-oxidized arterial grafts have superior patency in the CFV, and comparable patency in the CFA. Preliminary results demonstrate that these xenografts are stable and without degenerative changes. If corroborated by long-term data, these grafts may be a suitable alternative to currently available prosthetics for peripheral vascular reconstructive procedures.

BACKGROUND: Pulmonary vascular resistance is often elevated in patients with congestive heart failure, and in those undergoing left ventricular assist device (LVAD) insertion, it may precipitate right ventricular failure and hemodynamic collapse. Because the effectiveness of inotropic and vasodilatory agents is limited by systemic effects, right ventricular assist devices are often required. Inhaled nitric oxide (NO) is an effective, specific pulmonary vasodilator that has been used successfully in the management of pulmonary hypertension. METHODS: Eleven of 23 patients undergoing LVAD insertion met criteria for elevated pulmonary vascular resistance on weaning from cardiopulmonary bypass (mean pulmonary artery pressure > 25 mm Hg and LVAD flow rate < 2.5 L x min[-1] x m[-2]) and were randomized to receive either inhaled NO at 20 ppm (n = 6) or nitrogen (n = 5). Patients not manifesting a clinical response after 15 minutes were given the alternative agent. RESULTS: Hemodynamics for the group at randomization were as follows: mean arterial pressure, 72 +/- 6 mm Hg; mean pulmonary artery pressure, 32 +/- 4 mm Hg; and LVAD flow, 2.0 +/- 0.3 L x min(-1) x m(-2). Patients receiving inhaled NO exhibited significant reductions in mean pulmonary artery pressure and increases in LVAD flow, whereas none of the patients receiving nitrogen showed hemodynamic improvement. Further, when the nitrogen group was subsequently given inhaled NO, significant hemodynamic improvements ensued. There were no significant changes in mean arterial pressure in either group. CONCLUSIONS: Inhaled NO induces significant reductions in mean pulmonary artery pressure and increases in LVAD flow in LVAD recipients with elevated pulmonary vascular resistance. We conclude that inhaled NO is a useful intraoperative adjunct in patients undergoing LVAD insertion in whom pulmonary hypertension limits device filling and output.

BACKGROUND: Inhaled nitric oxide has been shown to be a potent and selective pulmonary vasodilator. Reports of increases in left ventricular end-diastolic pressure and episodes of pulmonary edema during the clinical use of inhaled nitric oxide in patients with preexisting left ventricular dysfunction have raised concerns that this agent may have myocardial depressant effects. We therefore undertook a study of the effects of inhaled nitric oxide on myocardial contractility in a porcine model of ventricular failure and pulmonary hypertension. METHODS: After inducing heart failure in 10 pigs by rapid ventricular pacing, hemodynamic measurements and pressure-volume diagrams (by the conductance method) were obtained in six animals at baseline and during administration of inhaled nitric oxide at concentrations of 20 and 40 ppm. Myocardial contractile state was assessed by the end-systolic pressure-volume relationship and preload-recruitable stroke work, whereas diastolic function was measured in terms of the end-diastolic pressure-volume relationship and the pressure decay time constant T. RESULTS: Baseline hemodynamics reflected heart failure and pulmonary hypertension, and inhaled nitric oxide induced significant reductions in mean pulmonary artery pressure and pulmonary vascular resistance. Although left ventricular end-diastolic pressure increased during administration of inhaled nitric oxide, no changes were observed in measures of systolic or diastolic function. CONCLUSIONS: Inhaled nitric oxide reduced pulmonary vascular resistance but did not alter myocardial contractility or diastolic function. Increases in left ventricular end-diastolic pressure during inhaled nitric oxide therapy are therefore not due to myocardial depression and may be related to increases in volume delivery to the left side of the heart resulting from reduced pulmonary vascular resistance.

BACKGROUND: Preformed anti-human leukocyte antigen (HLA) antibodies delay heart transplantation in patients with left ventricular assist devices (LVAD) because of difficulty in finding crossmatch-negative donors. These antibodies may also be associated with adverse outcome after transplantation. METHODS: In a retrospective analysis of 40 patients with LVAD at Columbia-Presbyterian Medical Center between 1990 to 1996, age, sex, diagnosis, race, duration of support, transfusions, and infections were studied by univariate and multivariate analysis as predictors for development of either anti-HLA class I (anti-I) or anti-HLA class II (anti-II) immunoglobulin G (IgG) or M (IgM) antibodies. RESULTS: Eighteen (45%) patients had development of anti-I and 20 (50%) had development of anti-II antibodies over the study period. Median time for LVAD support was 142 days (range 35 to 439). Only total number of perioperative platelet transfusions predicted the development of anti-I IgG antibodies (p = .04). No other associations were found for development of anti-I IgM or anti-II antibodies of either IgG or IgM specificity. Patients who had development of anti-I IgG received a mean of 13.9 (SE +/- 2.6) units of platelets compared with a mean of 7.7 (SE +/- 2.3) units in those who did not (p = .01). By Kaplan-Meier analysis, at the median duration of follow-up, 8% of patients receiving < 6 units were predicted to have development of anti-I antibodies compared with 63% receiving > 6 units (p = .002). In the last 7 patients, leukocyte filters were used to decrease the antigenic load during platelet and red blood cell transfusions. Only 1 of 7 (14%) patients had development of anti-HLA antibodies compared with 31 of 33 (94%) in whom filters were not used (p < .005). CONCLUSIONS: These results indicate that platelet transfusion during LVAD implantation is a risk factor associated with development of HLA class I IgG antibodies. Use of leukocyte filters during platelet transfusion may decrease the risk of development of anti-HLA antibodies.