Preservation with high-pressure carbon monoxide better protects ex vivo rabbit heart function than conventional cardioplegic solution preservation / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the protective effect of high-pressure carbon monoxide for preservation of ex vivo rabbit heart graft in comparison with the conventional HTK cardioplegic solution preservation.</p><p><b>METHODS</b>Heart grafts isolated from 85 New Zealand rabbits were randomly divided into Naive group (n=5), HTK group (n=40) and CO group (n=40). The grafts underwent no preservation procedures in Naive group, preserved at 4 degrees celsius; in HTK cardioplegic solution in HTK group, and preserved at 4 degrees celsius; in a high-pressure tank (PO2: PCO=3200 hPa: 800 hPa) in CO group with Krebs-Henseleit solution perfusion but without cardioplegic solution. After preservation for 2, 4, 6, 8, 10, 14, 18, and 24 h, 5 grafts from the two preservation groups were perfused for 30 min with a modified Langendorff apparatus and examined for left ventricular systolic pressure (LVSP), left ventricular diastolic pressure (LVDP), arrhythmia score (AS), myocardial ultrestructure, and cardiac enzyme profiles.</p><p><b>RESULTS</b>After preservation for 6 to 24 h, the cardiac enzyme profiles and systolic and diastolic functions were significantly better in CO group than in HTK group, but these differences were not obvious between the two groups after graft preservation for 2 to 4 h. Significant changes in the myocardial ultrastructures occurred in the isolated hearts after a 24-h preservation in both CO and HTK groups, but the myocardial damages were milder in CO group.</p><p><b>CONCLUSION</b>Preservation using high-pressure carbon monoxide can better protect isolated rabbit heart graft than the conventional HTK preservation approach especially for prolonged graft preservation.</p>

Early surgical outcomes of coronary heart disease with severe ischemic mitral regurgitation / 南方医科大学学报

<p><b>OBJECTIVE</b>To summarize the experience with surgical treatment of coronary artery disease with severe ischemic mitral valve regurgitation (IMR).</p><p><b>METHODS</b>From January 2006 to December 2009, 45 patients (35 males, 10 females aged 32-74 years) with the diagnosis of coronary artery disease complicated by IMR underwent coronary artery bypass grafting (CABG) combined with mitral valve plasty (MVP, 24 cases) or mitral valve replacement (MVR, 21 cases).</p><p><b>RESULTS</b>Perioperative deaths occurred in 2 cases due to multiple organ failure (MOF). Echocardiography showed a significant reduction of the mitral regurgitation area (from 11.80∓2.45 cm(2) to 2.83∓0.98 cm(2), t=22.80, P=0.00) after CABG combined with mitral valve surgery, with also significantly reduced postoperative left ventricular end diastolic diameter (LVEDD) (from 57.61∓10.06 mm to 51.84∓8.98 mm, t=2.85, P=0.005). No significant difference was detected in the left ventricular ejection fraction after the operation [(52.7∓15.4)% vs (53.2∓13.2)%, t=0.16, P=0.87)].</p><p><b>CONCLUSIONS</b>CABG combined with mitral valve surgery can improve early postoperative left ventricular function in patients with ischemic coronary heart disease complicated by severe mitral regurgitation, but further follow-up study is still needed for evaluation of the long-term results.</p>

Surgical treatment of 128 cases of constrictive pericarditis / 南方医科大学学报

<p><b>OBJECTIVE</b>To summarize the experience with surgical treatment of constrictive pericarditis.</p><p><b>METHODS</b>A retrospective analysis of the post-operative clinical data was conducted in 128 surgical patients with chronic constrictive pericarditis.</p><p><b>RESULTS</b>Two early postoperative death occurred in this group due to severe low cardiac output syndrome, with the mortality rate of 1.57%. The postoperative complications included low cardiac output syndrome (13.2%), arrhythmia (7.02%), acute renal insufficiency (3.9%), respiratory insufficiency (3.1%), wound infection (2.3%), postoperative chest bleeding (1.6%) and cerebral infarction (0.78%). Relapse occurred in one case because of incomplete pericardial resection.</p><p><b>CONCLUSIONS</b>Constrictive pericarditis should be confirmed as soon as possible with actively surgery, and the extent of pericardial resection should be decided according to the individual conditions. Complete untethering of the diseased pericardium should be performed with active prevention of postoperative complications.</p>

Early and mid-term results after 17 mm St Jude Regent mechanical valve replacement in 44 patients with small aortic root / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the changes in the cardiac function after St. Jude Regent mechanical valve replacement and assess the prosthesis-patient matching.</p><p><b>METHODS</b>From October 2007 to March 2009, 44 patients received implantation of 17 mm St. Jude aortic prostheses in our hospital. The patients were followed up for clinical symptoms, signs, electrocardiogram (ECG), echocardiogram and cardiac functions, and the results were compared with those of randomly selected 44 patients receiving 21 mm St. Jude aortic prostheses.</p><p><b>RESULTS</b>In 17 mm St Jude Medica Regent valve group, 8 patients presented with ECG ST segment changes, 3 complained of chest tightness, 3 had occasional chest pain and discomfort, and 8 had grade II and 4 grade III cardiac function. In 21 mm St Jude Medical Regent valve group, 6 patients had ECG ST segment changes, 2 complained of chest tightness, 2 reported occasional chest pain and discomfort, 11 had grade II and 2 grade III cardiac function. No significant differences were found in these indices between the two groups (P=0.32). Compared with those before operation, the two groups showed significant improvements in the left ventricular end-diastolic diameter, left ventricular posterior wall thickness, left ventricular mass index, and aortic pressure gradient (P<0.05). A significant increase in the left ventricular ejection fraction occurred 6-12 months after operation, but without statistical difference between the two groups (P>0.05).</p><p><b>CONCLUSION</b>For underweight patients (<60 kg) and those with small body surface area (<1.6 cm(2)), 17 mm St. Jude Medical Regent valve prosthesis may produce good therapeutic effect, and some indices are even close to those after placement of 21 mm St. Jude Medical Regent valve prosthesis. No obvious prosthesis-patient mismatch occurs after the placement of the 17 mm valve prosthesis and aortic valve ring expansion is not necessary.</p>

Transepicardial autologous transplantation of bone marrow mononuclear cells for acute myocardial infarction / 南方医科大学学报

<p><b>OBJECTIVE</b>To test the effect of intramyocardial injection of autologous bone marrow mononuclear cells (MNCs) in improving the cardiac function and myocardial revascularization in miniswine models of myocardial infarction.</p><p><b>METHODS</b>The miniswine models of myocardial infarction established by ligation of the anterior descending coronary artery were divided into 3 groups including a control and two MNC injection groups. Autologous bone marrow MNCs were injected via the epicardium into the infarcted area in the latter two groups at 1 and 2 weeks after the infarction, respectively. The ventricular segmental wall motion was evaluated after the treatment, and the infarcted myocardium observed with immunohistochemistry on frozen sections.</p><p><b>RESULTS</b>The left ventricular segmental wall motion differed significantly between the control and the MNC injection groups at 1 and 2 months after the treatment. CM-DiI-positive cells were detected in the infarcted myocardium where MNCs were implanted.</p><p><b>CONCLUSION</b>Intramyocardial injection of autologous bone marrow MNCs improves the infarcted ventricular segmental wall motion, and significantly increases the number of blood vessels in the infracted area. The transplanted cells can be integrated into the vascular walls of the capillaries and arterioles and differentiate into cardiomyocytes.</p>