Kentaro Umezu

Cardiac valvular surgery in dialysis patients: comparison of surgical outcome for mechanical versus bioprosthetic valves

PurposeThere has been a changing preference for bioprosthetic valves over mechanical valves in dialysis patients, but there is still much controversy. We reviewed our 17-year experience and assessed the influence of prosthesis choice.MethodsFrom 1990 to 2007, a total of 63 consecutive dialysis patients who underwent valvular surgery (64 operations including one reoperation) at our hospital were retrospectively reviewed. The mean age of the patients was 58.3 ± 9.0 years. The reasons for dialysis were glomerulonephritis (n = 32) and diabetes (n = 10). The major preoperative diagnosis was aortic stenosis (n = 44). The surgical procedures included aortic valve replacement (n = 44), mitral valve replacement (n = 7), double valvular replacement (n = 7), and mitral valve repair (n = 5). Prostheses for valve replacement were mechanical valves (n = 37) or bioprosthetic valves (n = 22). Follow-up was accomplished in 95.2%, and the mean follow-up period was 49 months.ResultsActuarial survivals at 1, 5, and 10 years were 85%, 64%, and 45% respectively. Freedom from cardiovascular events at 1 and 5 years was 61% and 41%, respectively. Mechanical valve patients had significantly higher early mortality than bioprosthetic valve patients (P = 0.03). However, both mechanical and bioprosthetic valve patients had similar survival and event-free rates (P = 0.87 and P = 0.27, respectively) in the midterm results. The mechanical group had a higher rate of bleeding events. There was no structural valve deterioration up to the 5-year follow-up.ConclusionThe choice of prosthesis did not influence the surgical outcome except for early mortality. Careful consideration of preventive measures against bleeding is important, and prosthesis selection should be based on the patient’s profile as well as the criteria for nondialysis patients.

Do we need fenestration when performing two-staged total cavopulmonary connection using an extracardiac conduit?

Between August 1999 and December 2007, 72 consecutive patients with single ventricle physiology underwent a modified Fontan procedure after a bidirectional Glenn shunt using an extracardiac polytetrafluoroethylene conduit without fenestration. Nitric oxide gas inhalation was commenced just after cardiopulmonary bypass together with intravenous phosphodiesterase III inhibitor administration. After oral intake was started, pulmonary vascular dilators such as beraprost, sildenafil, bosentan were given orally according to amount of chest drainage and patients condition. After discharge, oxygen therapy at home was continued for three months. No hospital death occurred after surgery. All patients were followed by our institute and follow-up period was 44.2+/-26 (36-106.8) months. One late death occurred during this follow-up period after re-operation. Cardiac catheterization after the Fontan completion showed transpulmonary gradient of 5.9+/-2.4 mmHg, systemic output of 3.4+/-2.1 l/min m2. Arterial oxygen saturation (SaO(2)) at the latest outpatient visit was 94.4+/-3.8%. According to our clinical experience with two-staged total cavopulmonary connection using an extracardiac conduit without fenestration, fenestration in the Fontan circuit is not necessary when performing the Fontan completion. Two-staged extracardiac total cavopulmonary connection without fenestration can be satisfactorily completed with the aid of pulmonary vasodilation therapy.

Second-Stage Palliation After Bilateral Pulmonary Artery Bands for HLHS and its Variants—Which is Better, Modified Norwood or Norwood Plus Bidirectional Glenn?

Background. The purpose of this study was to evaluate the surgical outcomes and pulmonary artery (PA) development associated with a new strategy wherein the modified Norwood (N) procedure is performed at 1-2 months after bilateral pulmonary artery banding (PAB). Methods. Between January 2008 and February 2010, 16 patients underwent Norwood-type operation after previous bilateral PAB. For analysis, patients were divided into two groups. Group I (n = 11) underwent modified Norwood procedure with either right modified Blalock Taussig (RMBT) shunt (n = 4) or right ventricle to pulmonary artery (RV-PA) conduit (n = 7). Group II (n = 5) underwent Norwood procedure plus bidirectional Glenn anastomosis. Diagnoses were hypoplastic left heart syndrome in 6 and its variants in 10. Results. There was no surgical death and no late death. Pulmonary artery interventions were performed at the time of the Norwood procedure in 27% in Group I and in 100% in Group II (p < 0.05). Additional PA interventions were performed during the period of follow-up in 4 cases in Group I (36.4%), and in 4 cases in Group II (80.0%). Additional Blalock Taussig shunts were performed in 7 patients, resulting in significant increase in PA index. In all, four patients have reached total cavopulmonary connection, and one has undergone biventricular repair. Eight patients in Group I and one patient in II Group reached bidirectional Glenn anastomosis. In Gp II, two patients showed LPA narrowing or obstruction with PA index of 80 ± 12 mm2/m2. Conclusions. Regarding the second-stage palliation after bilateral PAB, modified Norwood procedure with either RMBT or RV-PA conduit has some advantages compared with Norwood plus BDG with respect to subsequent pulmonary artery development. Additional BT shunt may contribute to PA development, even in the patients with Norwood procedure with RV-PA conduit.

Successful repair for a giant coronary artery aneurysm with coronary arteriovenous fistula complicated by both right- and left-sided infective endocarditis

We report a rare case of a 65-year-old woman who underwent an emergent lifesaving heart operation for an undiagnosed right coronary artery aneurysm with a coronary arteriovenous fistula complicated by active infective endocarditis, which affected the aortic valve, mitral valve, and coronary sinus. We performed direct closure of the coronary arteriovenous fistula, ligation of the right coronary artery aneurysm, double coronary artery bypass grafting, and double valvular replacement. Five years after the operation, she had no sign of congestive heart failure or infection, and was not receiving antibiotics.

Successful staged Fontan completion for a tricuspid atresia patient with left ventricular non-compaction.

We report a case of Fontan completion for a tricuspid atresia (TA) patient with left ventricular non-compaction (LVNC). The patient was diagnosed with TA (Ia) with LVNC by fetal echocardiography. Because the unfavourable prognosis of LVNC was anticipated, Imidapril as well as Carvedilol were administered to improve cardiac function, from the early stages of infancy. Staged Fontan completion with fenestration was successfully achieved with improvement of LV function.

Unilateral absence of right proximal pulmonary artery in the setting of severe pulmonary hypertension: considerations for surgical repair and perioperative management

We report a successfully treated case of unilateral absence of a pulmonary artery, associated with an atrial septal defect and chronic lung disease with severe pulmonary hypertension. Because this severe pulmonary hypertension could jeopardize postoperative hemodynamic, the ingenuity of surgical strategy was required. The atrial septal defect was left open as a safety “pop-off” valve, and prosthetic graft was chosen as a reconstructive material to avoid excessive dilatation from exposure to unpredictable postoperative pulmonary hypertension.

Aortic arch thrombosis in the neonate.

Aortic arch thrombosis (AAT) of the neonate is rare but life-threatening by fatal compromise associated with thrombotic obstruction of the ascending aorta. We report a neonate with AAT who demonstrated a severe coarctation of the aorta and cerebral hypo-perfusion immediately after birth. Echocardiography confirmed the diagnosis of AAT on the findings of a large thrombus located on the transverse arch and blocking the cervical arterial branches. Low-molecular-weight heparin reduced the size of the thrombus and improved the hemodynamics of coarctation and cerebral perfusion. Echocardiography is a powerful tool to make a diagnosis and to monitor the size and regression of AAT.

Fontan completion after Norwood with bidirectional Glenn shunt: their haemodynamics and pulmonary artery configuration

OBJECTIVES We ranked the haemodynamics and pulmonary artery (PA) configurations of Norwood with bidirectional Glenn shunt (NW-G) patients among the other staged Fontan completion (conventional) patients in this study. METHODS Between August 2001 and April 2010, 91 consecutive patients completed staged Fontan operations. Among them, NW-G was performed in 11. RESULTS There was no operative or late death except in one case which resulted from a reoperation after Fontan completion. Although the age at bidirectional Glenn (BDG) and Fontan completion was younger in NW-G (4.2 vs. 10.9 months, P < 0.01, and 2.3 vs. 3.3 years, P < 0.01), the interval between BDG and Fontan completion was not significantly different in these groups (23.6 vs. 28.0 months, P = 0.71). On Fontan completion, the extracardiac conduit size was significantly different (16.4 vs. 17.7 mm, P < 0.01). However, the pulmonary artery size (PA index) and the PA pressure were not significantly different (165.4 vs. 205.1 mm(2)/m(2), P = 0.23, and 13.4 vs. 11.0 mmHg, P = 0.08). Particularly in hypoplastic left heart syndrome patients, the PA index was not significantly different between these groups (165.4 vs. 174.9 mm(2)/m(2), P = 0.59). CONCLUSIONS The NW-G patients could have a subsequent Fontan completion with good results. There was no significant difference with respect to Fontan completion.

Imaging of aortico-left ventricular tunnel by three-dimensional echocardiography

Aortico-left ventricular tunnel (ALVT) is a rare congenital heart disease presenting as congestive heart failure in the neonatal or early infantile period due to severe aortic regurgitation (AR). We presented a 1-month-old boy with ALVT, originally diagnosed by two-dimensional echocardiography; however, the detailed anatomical features were not ascertained. Real-time three-dimensional echocardiography (RT3DE) could provide clear images of the three-dimensional structures of ALVT, just the same as those of surgical findings. ALVT originated from the left coronary cusp and ran an oblique path to the subvalvular orifice, having a narrow segment in the middle. RT3DE is a clinically useful diagnostic tool to clarify the detailed anatomy of ALVT.