Patrick W. Domkowski

Evaluation of vacuum-assisted closure in the treatment of poststernotomy mediastinitis.

OBJECTIVE Poststernotomy mediastinitis, although infrequent, is a potentially life-threatening complication of cardiac surgery that continues to have a significant morbidity and mortality despite aggressive therapy. Vacuum-assisted closure uses controlled suction to provide evacuation of wound fluid, decrease bacterial colonization, stimulate granulation tissue, and reduce the need for dressing changes. METHODS One hundred two patients from Duke University Hospital, The Durham Veterans Administration Hospital, and referring institutions underwent vacuum-assisted closure treatment. There were 63 men and 39 women, with a mean age of 67. The infection was noticed between postoperative days 8 and 34, at which time the wounds were opened and debrided. RESULTS Ninety-six of the 102 patients received vacuum-assisted therapy while the remaining 6 underwent daily multiple dressing changes without vacuum-assisted therapy. Fifty-three of the 96 patients required only sternal debridement, followed by wound vacuum therapy and closure by secondary intention, while the remaining 43 had an additional procedure. Of these, 33 patients underwent omental transposition and 10 patients had a pectoralis flap. The length of stay for all patients was 27 +/- 12 days. This was related in part to intravenous antibiotics. Hospital mortality for all patients was 3.7% (4 patients). Two of these patients underwent vascular flap and succumbed to multisystemic organ failure, while the other 2 received only wound vacuum therapy following debridement and succumbed to overwhelming sepsis. CONCLUSION Vacuum-assisted drainage is an effective therapy for mediastinitis following debridement or before placement of a vascularized tissue flap.

Histological Evidence of Angiogenesis 9 Months After Transmyocardial Laser Revascularization

A 66-year-old white male with end-stage ischemic cardiomyopathy was referred to our center for transmyocardial laser revascularization (PLC Eclipse Surgical Technologies) in July 1999. The patient had a long history of interventions for his coronary artery disease, including multiple percutaneous transluminal coronary angioplasties, stent placement in 1991 and 1993, and coronary artery bypass grafting in 1987 and 1992. He was evaluated for a third bypass, but we determined he was not a suitable candidate because of his diffuse small vessel distal coronary artery disease. Given the limitations of conventional therapeutic options, the patient underwent transmyocardial laser revascularization in July 1999. Thirty transmural channels were lased in the ischemic anterior and lateral walls of the left ventricle. The patient tolerated the procedure well and received anginal relief for the following 6 months; he then experienced recurrent symptoms …

Robotically assisted versus conventional freehand technique during beating heart anastomoses of left internal thoracic artery to left anterior descending artery

BACKGROUND Although robotically assisted coronary arterial anastomoses are being performed clinically, the short-term and long-term quality and integrity of the left internal thoracic artery (LITA) to left anterior descending artery (LAD) anastomosis remains unknown. The goal of this study was to perform a histologic and angiographic assessment of porcine beating heart LITA to LAD anastomoses using either robotic assistance or a conventional freehand technique. METHODS Twelve pigs underwent beating heart LITA to LAD anastomoses using either the robotically assisted (n = 6) or conventional freehand techniques (n = 6). Quantitative histologic analysis was performed in all animals in order to determine the degree of vascular wall damage. Selective coronary arteriography was performed in all animals immediately after the procedure in order to evaluate anastomotic patency. The unpaired Students t test was used for all comparisons between groups. RESULTS There were no differences in vascular wall damage between the robotically assisted and freehand techniques. Postoperative angiography revealed no stenoses in either group. CONCLUSIONS Use of the robotically assisted technique for creation of a LITA to LAD anastomosis was not associated with increased histologic damage when compared with the freehand technique in a beating heart porcine model. Furthermore, there was no difference between the two techniques in postoperative patency rate. These results support further clinical investigation of robotically assisted coronary bypass surgery.

The role of nω-nitro-L-arginine in modulation of pulmonary vascular tone in the maturing newborn pig

Current therapeutic modalities for treatment of newborn pulmonary hypertensive crisis include but are not limited to the administration of nitric oxide (endothelium-derived relaxing factor). However, few data are available on the role of endogenously produced endothelium-derived relaxing factor in the modulation of pulmonary vascular tone in the neonate. In the current study, we investigated the acute effects of N omega-nitro-L-arginine (a potent competitive inhibitor of endothelium-derived relaxing factor synthase) on the pulmonary vasculature of anesthesized open-chest 48-hour-old (n = 8) and 2-week-old (n = 7) Yorkshire pigs. After baseline data were acquired, all animals received a 10 mg/kg per minute infusion of N omega-nitro-L-arginine for 10 minutes. To discern distal and proximal pulmonary arterial vessel changes, input mean and characteristic impedance were respectively determined. Pulmonary vascular resistance was also calculated (units determined in dyne.sec.cm-5 plus or minus the standard error of the mean). Results showed N omega-nitro-L-arginine infusion did not significantly alter baseline pulmonary arterial pressure (22,370 +/- 1473 dyne/cm2), pulmonary vascular resistance (5171 +/- 805 dyne.sec.cm-5), input impedance (6343 +/- 806 dyne.sec.cm-5), or characteristic impedance (2073 +/- 418 dyne.sec.cm-5) in 48-hour-old pigs. In 2-week-old pigs, infusion of N omega-nitro-L-arginine elevated pulmonary arterial pressure (18,162 +/- 1415 dyne/cm2 versus 23,838 +/- 1810 dyne/cm2, p = 0.015), pulmonary vascular resistance (810 +/- 137 dyne.sec.cm-5 versus 1519 dyne.sec.cm-5, p = 0.030), and input impedance (2302 +/- 251 dyne.sec.cm-5 versus 2900 +/- 255 dyne.sec.cm-5, p = 0.018). Characteristic impedance was not altered in 2-week-old pigs. These data indicate that N omega-nitro-L-arginine infusion resulted in pulmonary arteriolar vasoconstriction in 2-week-old pigs, but not in 48-hour-old pigs. This finding suggests that endothelium-derived relaxing factor does not modulate basal pulmonary arteriolar tone during the early newborn period, but does play a significant role in 2-week-old pigs. These data also suggest that the functional role for endothelium-derived relaxing factor is confined to the distal arteriolar pulmonary bed and does not extend to the larger proximal arterial vessels.

Leaflet Interstitial Cells

lular components of cardiac valves. Historically they have been referred to as fibroblasts, fibrocytes, interstitial cells, matrix cells, myofibroblasts and stromal cells. LIC reside throughout the valve layers, though they are more dense in the lamina spongiosa than the lamina fibrosa. Because they resemble fibroblasts in structure and participate in extracellular matrix turnover, their major function was originally thought to be valve matrix synthesis. Recently these cells have been found to possess characteristics of both synthetic, fibroblast-like cells and contractile, smooth muscle-like cells. This chapter will focus on studies of atrioventricular and aortic valve LIC in pig, rabbit, hamster, rat, mouse, and human, and the structural and functional characteristics of these cells.

Factors Affecting Cellular Viability During Preimplantation Processing

has long been suggested to be linked to cellular viability and extracellular matrix integrity at the time of implantation. Efforts to standardize processing procedures for valve transplantation and optimize the longevity of the valves provided the original impetus for researchers to examine the effects of each processing step. This chapter focuses on the series of studies that resulted from this work. As reviewed in the previous section, viability can be evaluated in a number of ways, depending on which parameters are of interest for the study. In this chapter, we summarize the results using various methodologies to assess the health of leaflet cells following preimplantation processing.