Chiung-Lun Kao

Protection of the brain by retrograde cerebral perfusion during circulatory arrest

Hypothermic circulatory arrest is commonly used to facilitate repair of complex congenital heart defects and aortic lesions and for complex neurosurgical procedures. However, extended periods of circulatory arrest may impair cerebral metabolism and cause ischemic injury. Retrograde cerebral perfusion has been applied recently in aortic surgery to protect the brain. From January 1991 to December 1993, 29 patients underwent emergency operations to repair acute type A aortic dissection with the aid of hypothermic circulatory arrest. Six patients received hypothermic circulatory arrest without retrograde cerebral perfusion with a rectal temperature of 16.4 degrees +/- 0.9 degrees C (mean +/- standard error of the mean, group 1). Retrograde cerebral perfusion during hypothermic circulatory arrest was performed in 15 patients with a rectal temperature of 15.9 degrees +/- 0.5 degrees C (group 2) and in eight patients with a rectal temperature of 21.7 degrees +/- 0.8 degrees C (group 3). The hypothermic circulatory arrest times were 25 +/- 4, 42 +/- 4, and 63 +/- 6 minutes, respectively (p < 0.05). The cardiopulmonary bypass times were 173 +/- 5, 184 +/- 7, and 143 +/- 6 minutes, respectively (p < 0.05). All patients survived the operation and regained consciousness with no neurologic defects. Follow-up (mean 23.2, 14.5, and 5.1 months, respectively) was complete in all patients except one. This patient, from group 2, was killed in a road traffic accident 12 months after the operation. Our experience suggests that retrograde cerebral perfusion can effectively protect the brain from ischemic injury and extend the safe period of hypothermic circulatory arrest. With the aid of retrograde cerebral perfusion, prolonged circulatory arrest can probably be performed safely with moderate hypothermia.

Surgical management of thrombotic disc valve

Thrombotic obstruction, a rare but often fatal complication of cardiac valve prostheses, appears to occur more frequently in tilting-disc valves than in other valve designs. Its diagnosis and surgical treatment remain a challenge. Ten consecutive patients who had thrombosis of a tilting-disc valve prosthesis were treated in Chang Gung Memorial Hospital from November 1982 to August 1990. Preoperative clinical features, including exertional dyspnea, new murmur, and absence of a metallic click from the prosthetic valve, occurred in all of the patients. Symptoms were present for 1 week or more before reoperation in 70% of the patients; nevertheless, many patients were referred only after acute exacerbation of heart failure and development of pulmonary edema. Echocardiography confirmed prosthetic valve malfunction in 90% of the patients. One unconfirmed case was later documented by cardiac catheterization. Anticoagulant therapy was in the therapeutic range for only half of the patients at the time of admission. Prompt reoperation was performed for thrombectomy (8 patients, all survived) or valve replacement (2 patients, one death). Long-term outcome was satisfactory in all survivors with a mean follow-up of 31.6 months. These findings emphasize the importance of considering the diagnosis of thrombosis in patients with mechanical heart valve prostheses who are first seen with nonspecific symptoms and minor changes of their physical findings. The diagnosis could be easily made by echocardiography. Thrombectomy is an easy, fast, and safe procedure, especially for these critically ill patients.

Brown tumor of the sternum

The skeletal changes of severe hyperparathyroidism, known as osteitis fibrosa cystica, are now rarely encountered, because hyperparathyroidism is currently being diagnosed and treated at an early stage. Herein, a case of brown tumor of the sternum is reported; our report adds histologic data on this type of tumor to the literature.

Mitral valve repair in uremic congestive cardiomyopathy

BACKGROUND There is limited reported experience on mitral valve repair in patients with chronic renal failure. This study was designed to evaluate the outcomes of mitral valve repair in patients suffering from congestive heart failure as a result of uremic cardiomyopathy and severe mitral regurgitation requiring chronic hemodialysis. METHODS From 1995 to 2002, 5 women, ages 41 to 64 years (53 +/- 8 years), with uremic congestive cardiomyopathy and end-stage renal disease on chronic hemodialysis who underwent mitral valve repair for severe mitral regurgitation were identified retrospectively and followed for clinical and echocardiographic outcomes. The preoperative New York Heart Association functional class was 3.8 +/- 0.45. RESULTS All patients had good results immediately after surgical mitral valve repair with no more than mild mitral regurgitation. During the follow-up at an average of 22.4 +/- 14.9 months (range, 3 to 41 months) postoperatively, all patients returned to New York Heart Association functional class I. Neither mitral calcification nor increasing peak transmitral gradient (or decreasing mitral valve orifice area) was notable by two-dimensional echocardiography. No reoperation was required. CONCLUSIONS Although accelerated calcification of the repaired mitral valve and high incidence of failure of the reconstruction had been reported in patients with end-stage renal disease, based on our experience we advocate mitral valve repair when this can be safely performed, especially in patients with uremic congestive cardiomyopathy, in view of the added advantage of retaining the native valve in such patients.

Tuberculous pseudoaneurysm of the femoral artery: a case report.

Pseudoaneurysm of the femoral artery is an extremely rare complication of tuberculosis. We present a case of tuberculous femoral pseudoaneurysm that was successfully treated with resection, direct anastomosis, and postoperative antituberculous chemotherapy.

Mitral valve–sparing operation in subaortic stenosis caused by anomalous papillary muscle and discrete subaortic stenosis

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Conduit-on-valve replacement of a degenerated mitral bioprosthesis with a bioprosthesis

Explantation of a degenerated mitral bioprosthesis with reimplantation of a new bioprosthesis is time-consuming and can be associated with several life-threatening complications. We developed a technique to simplify this procedure and avoid the complications by attaching a new bioprosthesis supported by a pericardium-covered Dacron tube to the intact stent.

Septal myectomy with loop electrosurgical electrode for hypertrophic obstructive cardiomyopathy

Excellent results have been described for surgical relief of left ventricular outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy. Transaortic septal myectomy is technically demanding, especially when the lesion extends deep to the midcavity of left ventricle. A loop electrosurgical electrode is used to satisfactorily circumvent this problem.

Double-switch Ross procedure

Aortic root replacement with pulmonary autograft (Ross procedure) is a valuable technique. However, the best material for right ventricular outflow tract reconstruction remains controversial. We report on the experience with use of an aortic autograft with reimplantation of the diseased aortic valve for right ventricular outflow tract reconstruction in 3 patients with satisfactory result.