Thomas S. Maxey

A prospectus on tissue adhesives

Tissue adhesives are common adjuncts in surgical practice. Fibrin sealants are the most prevalent adhesives today. Recently, new adhesives have been approved for use in the United States, including cyanoacrylates, albumin-based compounds, collagen-based compounds, glutaraldehyde glues, and hydrogels. This review summarizes all the available tissue adhesives, focusing on their current and prospective indications in the clinical forum.

Mitral repair is superior to replacement when associated with coronary artery disease.

Objective:To compare the outcomes of mitral repair and replacement in revascularized patients with ischemic mitral regurgitation. Summary Background Data:Combined coronary bypass (CABG) and mitral procedures have been associated with the highest mortality (>10%) in cardiac surgery. Recent studies have suggested that mitral valve replacement (MVR) with sparing of the subvalvular apparatus had comparable results to mitral repair when associated with CABG. Methods:Over the past 7 years, 54 patients had CABG/mitral repair versus 56 who had CABG/MVR with preservation of the subvalvular apparatus. The groups were similar in age at 69.2 years in the replacement group versus 67.0 in the repair group. We compared these 2 groups based on hospital mortality, incidence of complications including nosocomial infection, neurologic decompensation (stroke), pulmonary complication (pneumonia, atelectasis, and prolonged ventilation), and renal complications (acute renal failure or insufficiency). Results:The mitral repair group had a hospital mortality of 1.9% versus 10.7% in the replacement group (P = 0.05). Infection occurred in 9% of repairs compared with 13% of replacements (P = 0.59). The incidence of stroke was no different between groups (2 of 54 repairs vs. 2 of 56 replacements, P = 1.00). Pulmonary complication rate was 39% in repairs versus 32% in replacements (P = 0.59). Worsening renal function occurred in 15% of repairs versus 18% of replacements (P = 0.67). Conclusions:Mitral repair is superior to mitral replacement when associated with coronary artery disease in terms of perioperative morbidity and hospital mortality. Although preservation of the subvalvular apparatus with MVR has a theoretical advantage in terms of ventricular function, mitral repair clearly adds a survival benefit in patients with concomitant ischemic cardiac disease.

Beneficial effects of inhaled nitric oxide in adult cardiac surgical patients

BACKGROUND Pulmonary hypertension with associated right ventricular dysfunction may complicate the postoperative cardiac patient despite maximum pharmacologic and ventilatory support. The purpose of this study was to retrospectively review our experience with inhaled nitric oxide (INO) in adult postoperative cardiac patients with pulmonary hypertension. METHODS We retrospectively reviewed the medical records of 17 adult cardiac patients treated with INO postoperatively between November 1998 and February 2000. The INO was used to manage pulmonary hypertension postoperatively in patients who had undergone coronary artery bypass graft (CABG) (n = 13), valve operation (n = 3), and combined CABG/aortic valve replacement (n = 1). Hemodynamic and respiratory measurements before INO and again 6 hours after administration were examined. Students t test was used to analyze the data. RESULTS Inhaled nitric oxide (20 ppm to 30 ppm) was administered for a median duration of 30.2 hours. The group, as a whole, demonstrated a significant decrease in both mean pulmonary artery pressure and right ventricular stroke work index. In addition, a significant increase in posttherapeutic cardiac index and Pao2/Fio2 ratio was observed. The vasodilatory effects of nitric oxide were specific to the pulmonary circulation as no significant change in mean arterial pressure was noted. Overall mortality was 6%. CONCLUSIONS Inhaled nitric oxide effectively and selectively lowered right ventricular afterload and right ventricular work in critically ill adult cardiac patients with acute pulmonary hypertension.

Safety and efficacy of the supraclavicular approach to thoracic outlet decompression

BACKGROUND Thoracic outlet syndrome (TOS) is a clinical diagnosis encountered by both thoracic and vascular surgeons. The goal of surgical therapy involves relieving compression of the neurovascular structures at the superior thoracic aperture. The traditional approach to thoracic outlet decompression has been transaxillary; however more centers are moving toward a more tailored approach through a supraclavicular incision. METHODS The medical records of 67 patients who underwent surgical decompression between 1993 and 2001 for TOS were retrospectively reviewed. Patient demographics and early outcome were assessed through clinic follow-up. RESULTS Seventy-two thoracic outlet decompressions were performed on 67 patients with the diagnosis of TOS. Five patients underwent bilateral thoracic outlet decompression. All operations in this time period were safely accomplished through a supraclavicular approach. The syndromes associated with thoracic outlet compression were neurogenic (n = 59), venous (n = 10), and arterial (n = 3). Forty-six of 72 (63.9%) operations resulted in complete resolution of symptoms, 17 cases (23.6%) had partial resolution, and 9 patients (12.5%) had no resolution. There were no deaths and morbidity was minimal with 6 complications (8.3%). CONCLUSIONS The supraclavicular approach is a safe and effective technique in managing all forms of thoracic outlet compression.

The beating heart approach is not necessary for the dor procedure

BACKGROUND Ventricular reconstruction using the Dor technique has been demonstrated to improve outcome in patients with dilated left ventricles. It has been suggested that a beating heart approach improves ventricular function by allowing the surgeon to palpate that part of the ventricle to exclude. METHODS We performed a retrospective analysis of patients who underwent an endoventricular circular patch plasty (Dor procedure) between 1998 and 2001. All patients who received ventricular restoration, with or without revascularization or valve repair, were included in the analysis. Discrete left ventricular aneurysms were excluded. Patients were divided into two groups: group 1 (n = 15) underwent ventricular reconstruction with the beating heart technique, whereas group 2 (n = 38) underwent restoration with the aorta cross-clamped. Clinical and hemodynamic data were collected from medical records and computerized databases and compared between the two groups. RESULTS Fifty-three patients underwent endoventricular circular patch plasty. All patients had enlarged ventricles (echocardiogram demonstrating unidimensional end-diastolic diameter >/= 6.0 cm) and echocardiographic evidence of severe left ventricular dysfunction (mean ejection fraction: group 1 = 21.4%; group 2 = 23.4%). No operative mortalities occurred in either group and all patients were discharged home alive (mean postoperative hospital stay 8.3 days [6 to 22 days]). All patients had improvement in left ventricular function with mean postoperative left ventricular ejection fraction of 36.9% (25% to 52%) in group 1 versus 38.1% (31% to 50%) in group 2, p = 0.081. Ventricular arrhythmias occurred in 5 of 15 group 1 patients and in 9 of 38 group 2 patients. Two patients in the entire cohort (1 patient in group 1, and 1 patient in group 2) had at least one readmission within 12 months with evidence of heart failure. The group 1 patient went on to successful transplant 11 months later, whereas the group 2 patient died 10 months later. CONCLUSIONS These results demonstrate that the Dor technique of ventricular restoration significantly improves left ventricular function and the beating heart approach provides no additional advantage over continuous aortic cross clamping.

Early adenosine receptor activation ameliorates spinal cord reperfusion injury

Objectives Adenosine receptor activation at reperfusion has been shown to ameliorate ischemia–reperfusion injury of the spinal cord, but the effects of therapy given in response to ischemic injury are unknown. We hypothesized that adenosine receptor activation with ATL-146e would produce similar protection from ischemic spinal cord injury, whether given at reperfusion or in a delayed fashion. Methods Twenty-two New Zealand white rabbits were divided into three groups. All three groups, including the ischemia–reperfusion group (IR, n = 8), underwent 45 min of infrarenal aortic occlusion. The early treatment group (early, n = 8) received 0.06 μg/kg/min of ATL-146e for 3 h beginning 10 min prior to reperfusion. The delayed treatment group (delayed, n = 6) received ATL-146e starting 1 h after reperfusion. After 48 h, hind limb function was graded using the Tarlov score. Finally, lumbar spinal cord neuronal cytoarchitecture was evaluated. Results Hemodynamic parameters were similar among the groups. Hind limb function at 48 h was significantly better in the early group (3.5 ± 1.0) compared to the IR group (0.625 ± 0.5, P ≤ 0.01). There was a trend towards better hind limb function in the early group compared to the delayed group (2.4 ± 1.1, P = 0.08). Hind limb function was similar between delayed and IR groups. Hematoxylin–eosin spinal cord sections demonstrated preservation of viable motor neurons in the early group compared to the delayed and IR groups. Conclusions Early therapy with ATL-146e provided better protection in this study; therefore, therapy should not be delayed until there is evidence of ischemic neurological deficit. This study suggests that adenosine receptor activation is most effective as a preventive strategy at reperfusion for optimal protection in spinal cord ischemia–reperfusion injury.

Transverse arch hypoplasia may predispose patients to aneurysm formation after patch repair of aortic coarctation

BACKGROUND Thoracic aortic aneurysm after patch repair of aortic coarctation is a potentially lethal complication. We hypothesized that transverse arch hypoplasia in association with patch repair of aortic coarctation predisposes aneurysm formation. METHODS A retrospective analysis was performed on all patients undergoing isolated aortic coarctation repair at the University of Virginia Health Systems between 1970 and 1995. Of 244 repairs, 38 patients underwent patch repair. These 38 patients were divided into two groups. The aneurysm group (n = 15) had aortic aneurysms develop at the repair site, which required aneurysmectomy. The nonaneurysm group (n = 23) did not have any aneurysms develop. Univariate analysis and Fishers exact text were used to identify factors that independently predict aneurysm formation. RESULTS Univariate analysis demonstrated aortic arch hypoplasia associated with patch repair independently predicts future aneurysm formation (p < 0.01). Patients who had an aneurysm develop also had a similar incidence of bicuspid aortic valves, mild restenosis, and late hypertension compared with patients in the nonaneurysm group. CONCLUSIONS Aneurysm formation after patch repair of aortic coarctation develops into a subgroup of patients. Aortic arch hypoplasia associated with coarctation independently predicts future aneurysm formation.