Cardiopulmonary Bypass in a Patient with Factor XII Deficiency.

The performance of cardiopulmonary bypass (CPB) in the factor XII-deficient patient is challenging in that the normal method for monitoring anticoagulation is ineffective as a result of an impaired contact activation system. We report the case of a factor XII-deficient patient who underwent surgical revascularization on CPB. His factor XII level was replenished with fresh-frozen plasma immediately before surgery. This management strategy lowered the baseline activated clotting time (ACT) to near normal, providing a meaningful ACT value for CPB. Factor XII is also a key component in the fibrinolytic system and its deficiency is associated with increased thrombosis. Because the factor XII level quickly returns to baseline postoperatively, perioperative care must include strategies to avoid postoperative thromboembolic events.

Dysregulation of antioxidant mechanisms contributes to increased oxidative stress in calcific aortic valvular stenosis in humans.

OBJECTIVES: The aim of this study was to determine whether oxidative stress is increased in calcified, stenotic aortic valves and to examine mechanisms that might contribute to increased oxidative stress. BACKGROUND: Oxidative stress is increased in atherosclerotic lesions and might play an important role in plaque progression and calcification. The role of oxidative stress in valve disease is not clear. METHODS: Superoxide (dihydroethidium fluorescence and lucigenin-enhanced chemiluminescence), hydrogen peroxide H2O2 (dichlorofluorescein fluorescence), and expression and activity of pro- and anti-oxidant enzymes were measured in normal valves from hearts not suitable for transplantation and stenotic aortic valves that were removed during surgical replacement of the valve. RESULTS: In normal valves, superoxide levels were relatively low and distributed homogeneously throughout the valve. In stenotic valves, superoxide levels were increased 2-fold near the calcified regions of the valve (p < 0.05); noncalcified regions did not differ significantly from normal valves. Hydrogen peroxide levels were also markedly elevated in calcified regions of stenotic valves. Nicotinamide adenine dinucleotide phosphate oxidase activity was not increased in calcified regions of stenotic valves. Superoxide levels in stenotic valves were significantly reduced by inhibition of nitric oxide synthases (NOS), which suggests uncoupling of the enzyme. Antioxidant mechanisms were reduced in calcified regions of the aortic valve, because total superoxide dismutase (SOD) activity and expression of all 3 SOD isoforms was significantly decreased. Catalase expression also was reduced in pericalcific regions. CONCLUSIONS: This study provides the first evidence that oxidative stress is increased in calcified regions of stenotic aortic valves from humans. Increased oxidative stress is due at least in part to reduction in expression and activity of antioxidant enzymes and perhaps to uncoupled NOS activity. Thus, mechanisms of oxidative stress differ greatly between stenotic aortic valves and atherosclerotic arteries.

Latest developments in the field of assisted circulation.

The 51st Annual Meeting of the American Society for Artificial Internal Organs was held in Washington, DC, June 9 to 11, 2005. The abstract submission deadline for this meeting occurred on January 14, 2005. To ensure that the attendees were completely up-to-date with developments in the field of mechanical circulatory support, I was asked to provide a brief summary of developments or milestones that occurred after the abstract submission deadline. The list of highlights included in this manuscript was selected from an informal poll of colleagues and industry representatives, as well as a review of press releases and government- and industry-sponsored Web sites. Any omissions or errors in this summary of the latest developments in the field of mechanical circulatory support are entirely my responsibility. I also want the reader to understand that I have no financial interest in any of the device manufacturing companies to which I will refer.

Long-term (2-year) clinical events following transthoracic intramyocardial gene transfer of VEGF-2 in no-option patients.

BACKGROUND: The short-term clinical impact of intramyocardial gene transfer (GT) of the angiogenic protein vascular endothelial growth factor-2 (VEGF-2) has been previously reported to significantly reduce Canadian Cardiovascular Society (CCS) angina class and to prolong exercise treadmill test (ETT) time. We describe the safety and long-term events (>1 year) in consecutive, nonrandomized, patients who received intramyocardial VEGF-2. METHODS: Thirty patients with intractable CCS class III or IV angina and no options for revascularization underwent direct intramyocardial GT of VEGF-2 naked DNA via limited thoracotomy at total doses of 0.2, 0.8, or 2.0 mg. Patients were followed for clinical events after 1 year by hospital records, follow-up visits or telephone contact. Due to one perioperative death, 29 patients were followed. RESULTS: At a mean follow-up of 751 +/- 102.5 days (range 459-959) there were four deaths (13.8%), five myocardial infarctions (MIs) (17.2%), and seven revascularization procedures (24.1%). There were 15 hospitalizations in 12 patients. At the end of the follow-up period no patient (0%) had CCS class IV angina, 3 patients (11.5%) had class III angina, and 23 (88.5%) had class I to II angina. There were two new diagnoses of cancer. CONCLUSION: Transthoracic intramyocardial injection of VEGF-2 is associated with an improvement of symptoms of angina in the majority of patients beyond the first year of treatment. Major clinical events such as death, MI, and repeat revascularization are uncommon during the first year but more frequent after 1 year at a rate consistent with the severity of underlying disease in this population with advanced atherosclerosis. The majority of events were the result of progression of disease in areas of the heart remote from the site of GT. A large randomized trial is planned to determine the efficacy of intramyocardial VEGF-2 injections in inoperable patients.

Enhanced cytomegalovirus infection in atherosclerotic human blood vessels.

Human cytomegalovirus (CMV) is a possible co-factor in atherogenesis and vascular occlusion, but its ability to actively infect medium and large blood vessels is unclear. A vascular explant model was adapted to investigate CMV infection in human coronary artery, internal mammary artery (IMA), and saphenous vein (SV). Vascular explants were inoculated with CMV Towne or low-passage clinical isolate and examined in situ for CMV cytopathic effect and immediate-early and early antigens, as indicators of active infection. At 5 to 7 days after inoculation, we found that CMV Towne actively infected eight of eight different atherosclerotic blood vessel explants (coronary artery, n = 4; SV and IMA grafts, n = 4), whereas it only infected 2 of 14 nonatherosclerotic blood vessel explants (SV, n = 10; IMA, n = 4) (P = 0.001). The CMV clinical isolate actively infected none of six sets of nonatherosclerotic SV explants at 5 to 7 days after inoculation. The active CMV infections involved adventitial and, less frequently, intimal cells. A small subset of infected cells in atherosclerotic tissue expresses the endothelial cell marker CD31. Smooth muscle cells residing in both atherosclerotic and nonatherosclerotic blood vessels were free of active CMV infections even after all vascular tissue layers were exposed to the virus. In contrast, active CMV Towne infection was evident at 2 days after inoculation in smooth muscle cells and endothelial cells previously isolated from the SV tissues. We conclude that active CMV infection is enhanced in atherosclerotic blood vessels compared to atherosclerosis-free vascular equivalents, and this viral activity is restricted to subpopulations of intimal and adventitial cells.

Low-level endotoxin induces potent inflammatory activation of human blood vessels: inhibition by statins.

BACKGROUND: Low-level endotoxemia (ie, >or=50 pg/mL) in apparently healthy subjects was recently identified as a powerful, independent risk factor for atherosclerosis. METHODS AND RESULTS: We treated human saphenous veins (HSVs) with low levels of endotoxin. Release of the proinflammatory chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) was measured by ELISA. Superoxide was determined by using the fluorescent probe dihydroethidium (HE), and monocyte binding was assessed with calcein-labeled U-937 cells. Three- to 4-fold increases in MCP-1 and IL-8 release were observed at endotoxin concentrations of 100 pg/mL; these increases were inhibited by the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin. Studies in cultured endothelial cells suggest that the mechanism is related to inhibition of isoprenylation (ie, geranylgeranylation) rather than cholesterol formation. Endotoxin produced dose-dependent increases in HE fluorescence that were inhibited by the superoxide dismutase mimics Tiron and MnTBAP. Endotoxin potently induced U-937 cell binding to HSV; binding was inhibited by both Tiron and atorvastatin. Toll-like receptor-4 expression was detected in cultured HSV endothelial and smooth muscle cells and in intact HSV. CONCLUSIONS: Clinically relevant levels of endotoxin, as reported in ambulatory populations, have profound inflammatory effects on intact HSV. Inhibition of endotoxin-induced vascular inflammation might contribute to the beneficial effects of statins in treating atherosclerosis.

Surgical management of patients in the REMATCH trial.

The donor shortage makes cardiac transplantation a less than ideal treatment for end-stage heart failure. The utility of the left ventricular assist device (LVAD) as a permanent form of circulatory support has recently been established in the REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) trial. In this report, we describe the surgical management of LVAD patients in REMATCH and their short-term outcomes. Between 1998 and 2001, 129 patients with end-stage heart failure, who were excluded from consideration for transplantation, were enrolled in the REMATCH clinical trial. Patients were randomized to two treatment arms: optimal medical management or HeartMate vented electric LVAD implantation. The primary end point of the study was death from any cause. Secondary end points included the incidence of serious adverse events, the duration of hospitalization, quality of life, and functional status. Sixty-eight patients received an LVAD, 55 (81%) of whom survived for longer than 1 month. The median intensive care unit and hospital lengths of stay (LOS) for those that survived at least 1 month were 15 and 34 days, respectively. Sixty-seven (99%) patients had a serious adverse event. The rates of perioperative bleeding, late bleeding, right heart failure, and sepsis were 0.42, 0.53, 0.15, and 0.53 events/patient-year, respectively. Factors predictive of a longer LOS for the implant hospitalization included sepsis, age, and late bleeding (p < 0.0001). The patients' New York Heart Association functional class improved significantly at 1 month compared with base line (p < 0.001). Functional class improved in LVAD-supported patients despite a high adverse event rate. Most adverse events occurred within 30 days of device implantation. Sepsis, age, and late bleeding were the major determinants of LOS.