Munetaka Masuda

Usefulness of fasudil, a Rho-kinase inhibitor, to treat intractable severe coronary spasm after coronary artery bypass surgery.

We have recently demonstrated that fasudil, a Rho-kinase inhibitor, is effective in suppressing coronary artery spasm in patients with vasospastic angina. Thus, blockade of Rho-kinase may provide a novel therapeutic strategy to treat ischemic coronary syndrome caused by the spasm. Severe coronary artery spasm still remains a life-threatening serious complication of coronary artery bypass grafting (CABG). In this study, we examined the inhibitory effect of fasudil in patients with intractable severe coronary spasm after CABG. Three patients who underwent CABG showed severe myocardial ischemia resistant to intensive therapy with intravenous conventional vasodilators, including isosorbide dinitrate (ISDN), diltiazem, and nicorandil. Coronary angiography revealed severe coronary spasm in native coronary arteries and/or bypass arterial grafts in all patients. Since intracoronary and/or intragraft administration of ISDN was ineffective to resolve the spasm, we then administered fasudil (1.5 mg/min for 15 minutes) into the spastic arteries. Fasudil successfully resolved the spasm and improved myocardial ischemia in all patients without any systemic adverse effects. In conclusion, the treatment with fasudil may be useful to treat intractable and otherwise fatal coronary spasm resistant to intensive conventional vasodilator therapy after CABG.

Myocardial Distribution of Retrograde Flow through the Coronary Sinus of the Excised Normal Canine Heart

Myocardial distribution of the retrograde flow through the coronary sinus in the canine heart was evaluated by observing the corrosion casts of the myocardial vessels after coronary sinus injection of a low-viscosity resin, Mercox, a compound that passes through capillaries. The apex and the left ventricular free wall were well perfused at the microvascular level, even in the presence of complete left main coronary artery occlusion, whereas the right ventricular free wall was not perfused effectively at this level in any heart. Although there was considerable variation in the perfusion of the ventricular septum from heart to heart, the entire septum was not perfused in some of the hearts. We considered this poor perfusion of the septum to be due to the presence of well-developed thebesian veins in the septum. Retrograde coronary sinus perfusion of cardioplegic solution may be a valuable alternative to protect the left ventricular free wall, especially in cases of critical coronary artery stenosis or occlusion. However, antegrade perfusion should be used also, whenever possible, for adequate protection of the septum and the right ventricular free wall.

Impacts of pulsatile systemic circulation on endothelium-derived nitric oxide release in anesthetized dogs

BACKGROUND The effects of pulsatile flow on endothelium-derived nitric oxide-mediated vasodilation are not fully elucidated in an in vivo model. METHODS A left ventricular assist device was established in 10 anesthetized dogs with a centrifugal pump and an air-driven pneumatic pump. The systemic circulation was subjected to step changes in the frequency of pulse (0, 30, 60, and 120 bpm with a fixed pulse pressure of 50 mm Hg), and in the amplitude of pulse (0, 20, and 50 mm Hg with a fixed pulse rate of 120 bpm). Hemodynamic variables and calculated total systemic vascular resistance were compared before and after the administration of N(G)-Nitro-L-arginine Methyl Ester (L-NAME) (20 mg/kg). Plasma NO2-/NO3- concentration levels were also measured. RESULTS Total systemic vascular resistance significantly decreased while plasma NO2-/No3- concentration increased in response to the rise in both pulse rate and pulse pressure. However, L-NAME significantly diminished these effects of pulsatile flow. CONCLUSIONS Both the frequency and the amplitude of pulse wave in the systemic circulation are significant independent stimuli for endothelium-derived nitric oxide-mediated vasodilation in vivo.

Comparative study of cell saver and ultrafiltration nontransfusion in cardiac surgery

Hemoconcentration for the establishment of no-donor blood transfusion in open heart surgery was assessed in regard to both the saving of protein and platelets and the exclusion of free hemoglobin. Two different types of hemoconcentrator were compared: the ultrafilter (group I, 6 patients) and the Cell Saver (group II, 6 patients). The total serum protein level, expressed as the percent recovery of the preoperative value, after hemoconcentration was significantly higher in group I (group I versus group II: total serum protein, 118% versus 87% [p less than 0.05]; fibrinogen, 77% versus 50% [p less than 0.01]; immunoglobulin, 83% versus 60% [p less than 0.01]). The platelets also seemed to be well preserved after hemoconcentration in group I. Although the exclusion of free hemoglobin from plasma was inferior in group I compared with group II, the postoperative plasma free hemoglobin level did not increase in group I. We conclude that use of the Cell Saver in nontransfusion cardiopulmonary bypass might cause a severe depletion of various proteins and that the ultrafilter is both safer and more useful if employed routinely.

Clinical results of arterial switch operation for double-outlet right ventricle with subpulmonary VSD

OBJECTIVE An arterial switch operation is considered a good alternative for the repair of double-outlet right ventricle (DORV) with atrioventricular concordance connection and subpulmonary ventricular septal defect (VSD) when intraventricular rerouting is not feasible. The clinical results of an arterial switch operation with ventricular septal defect closure for this anomaly were studied. METHODS Between 1986 and 1997, 27 patients ranging from 10 days to 5 years of age (mean 0.4 years) underwent an arterial switch operation with ventricular septal defect closure for the correction of double outlet right ventricle with subpulmonary VSD. The 50% rule was used to define double-outlet right ventricle. Arch anomalies were associated in nine cases, and were corrected either previously or simultaneously. A subarterial muscle resection was performed in 14 without any subsequent stenosis of the ventricular outflow tract. The relationship of the great arteries was mostly anteroposterior in 15 and mostly side by side in 12. The left coronary artery (main trunk or circumflex artery) courses behind the pulmonary artery in 15/27 (six/15 in the anteroposterior relation and ten/12 in the side by side relation). The Lecompte maneuver was used to reconstruct the pulmonary artery in all but five cases with a side by side relationship of the great arteries. RESULTS There was one operative death (3.7%) and three late deaths. The actuarial survival rate was 83 +/- 8% at 9 years. Right ventricular outflow tract obstruction including peripheral pulmonary stenosis developed in seven cases operated on in the early era. The reoperation free rate was 46 +/- 20% at 9 years. CONCLUSION Although double-outlet right ventricle with subpulmonary VSD has complex features, including an aortic arch obstruction and coronary artery anomalies, an optimal definitive surgical repair using an arterial switch operation can be performed safely with a thorough understanding of this variable anomaly. The prevention of right ventricular outflow tract obstruction at the time of an arterial switch operation may thus help improve the rate of late morbidity.

Postoperative cardiac rhythms with superior septal approach and lateral approach to the mitral valve

BACKGROUND The superior-septal approach provides an excellent view of the mitral valve and therefore has received considerable interest. However, the safety of this approach is controversial because it requires division of the sinus node artery in most cases. METHODS Postoperative cardiac rhythms were analyzed in 152 consecutive patients who underwent mitral valve procedures between January 1992 and February 1995 with a conventional right lateral left atriotomy (group 1, n = 69) or the superior-septal approach (group 2, n = 83). Follow-up ranged from 2 to 38 months, and the mean follow-up was 16.1 months in group 1 and 13.8 months in group 2. RESULTS The mortality rate was similar in the two groups (1.4% in group 1 and 1.2% in group 2), and the causes of death were not related to the left atriotomy. At discharge, 96% of the patients in group 1 who were in sinus rhythm preoperatively and 78% of those in group 2 remained in sinus rhythm. At the last follow-up, 88% of these patients in group 1 and 83% in group 2 remained in sinus rhythm. Among the patients in atrial fibrillation or junctional rhythm before operation, 12% in group 1 and 11% in group 2 had regained sinus rhythm at the last follow-up. There were no significant differences in these values. CONCLUSIONS Although the incidence of dysrhythmias was higher with the superior-septal approach in the early postoperative period, this approach provides an excellent operative view of the mitral valve and similar results in terms of late postoperative cardiac rhythms as the right lateral left atriotomy.

Long-term results of isolated tricuspid valve replacement

The long-term outcome of isolated tricuspid valve replacement is unclear because this procedure is rare and usually performed in combination with replacement of other valves. The results of all 31 isolated tricuspid valve replacements carried out in 23 patients in Kyushu University Hospital between 1975 and 2004 were retrospectively reviewed. A bioprosthesis was used in 27 cases and a mechanical valve in 4. There were 2 operative deaths and 4 late deaths. One patient with a mechanical prosthesis needed redo tricuspid valve replacement due to valve thrombosis 6 months after surgery. The mean cardiothoracic ratio and functional class improved significantly postoperatively. At 15 years after tricuspid valve replacement, actuarial survival was 75.6% and freedom from valve-related events was 84.9%. For bioprostheses, freedom from structural valve deterioration at 5, 10 and 15 years was 95.2%, 95.2% and 85.7%, respectively. The long-term results of tricuspid valve replacement are considered satisfactory, and a bioprosthesis can be recommended due to its good outcome and no need for anticoagulation. We should not wait until the development of endstage cardiac impairment before carrying out tricuspid valve surgery.

Extensive use of polytetrafluoroethylene artificial grafts for prolapse of bilateral mitral leaflets

OBJECTIVES There are an increasing number of reports concerning mitral valve repair by reconstruction of the chordae tendinae with the use of expanded polytetrafluoroethylene (PTFE) sutures. However, little information is available about the extended application or results of this technique for extended prolapse of bilateral mitral leaflets, which is considered to be difficult to repair. METHODS Between October 1993 and May 1998, 17 patients (age range 16-74 years) who had from moderate to severe mitral regurgitation as the result of a prolapse of bilateral leaflets underwent mitral valve repair by reconstruction of artificial chordae with CV-4 expanded PTFE sutures. Either bilateral or unilateral Kays suture annuloplasty was also performed to correct annular dilatation in all patients. RESULTS No operative death or late mortality was observed. Before discharge, immediate postoperative echocardiography showed less than moderate mitral regurgitation in 16 of 17 patients. The follow-up was completed in all cases by a clinical examination and serial echocardiograms, and the median follow-up period was 52 months (range 27-82 months). There was one failure that required re-operation because of worsening mitral regurgitation (elongation of the anchored side of papillary muscle). When the re-operated patient was excluded from the following data, the degree of mitral regurgitation, estimated by echocardiography performed at recent follow-up, was none in four patients, trivial in eight patients, and mild in four patients. The systolic and diastolic dimensions of the left ventricle decreased significantly (P<0.01). CONCLUSIONS Because replacement of artificial chordae was not complicated and seemed to preserve fine relationships among leaflet tissues, chordae, and papillary muscles, we therefore suggest that the extensive use of PTFE artificial chordae appears to be a promising procedure for the repair of all kinds of mitral lesions causing mitral regurgitation.

Minor Infection Encouraged by Steroid Administration during Cardiac Surgery

The aim of this study was to investigate whether steroid administration would increase the risk of postoperative infection. Sixty adults who underwent elective cardiac surgery under cardiopulmonary bypass were prospectively randomized into two groups. Thirty-one patients received hydrocortisone (50 mg·kg−1) before and after cardiopulmonary bypass, the other 29 served as controls. Various hemodynamic and pulmonary measurements were obtained perioperatively, and the white blood cell counts and levels of C-reactive protein were checked up to the 14th postoperative day. Steroid administration did not have any favorable effects during the perioperative period. Re-administration of antibiotics was needed in 7 patients (22.6%) after the 7th postoperative day in the steroid group, and in 3 (10.3%) in the control group. The peak white cell counts and C-reactive protein levels after the 7th postoperative day were significantly higher in the steroid group. Steroid administration offered no clinical benefit to patients undergoing cardiac surgery with cardiopulmonary bypass, and it may encourage minor infections in the late postoperative period.

Coronary reserve and contractile reserve in crystalloid- and blood-perfused rabbit hearts

SummaryCoronary reserve and contractile reserve were compared between crystalloid-perfused and bloodperfused rabbit hearts at various perfusion pressures (40–110mmHg). Contractile function of the crystalloidperfused hearts was dependent on the perfusion pressure, according to Greggs phenomenon. Developed left ventricular pressure (LVP) increased from 67 ± 6 mmHg to 121 ± 5 mmHg and positive dP/dt maximum (dP/dt max) from 1,083 ± 75 to 2,233 ± 126 mmHg/s at perfusion pressures between the lowest and highest perfusion pressure. In the blood-perfused hearts, the perfusion pressure-induced changes were less pronounced: developed LVP changed from 107 ± 11 mmHg to 138 ± 8mmHg and dP/dt max from 1,517 ± 181 to 2,008 ± 187mmHg/s. The blood-perfused hearts showed better cardiac function, especially negative dP/dt minimum (dP/dt min), compared to the crystalloidperfused hearts. Contractile reserve estimated by paired pacing technique was quite independent of the perfusion pressure in the blood-perfused hearts but not in the crystalloid-perfused hearts, and was significantly better in the blood-perfused hearts (e.g., 81% increase of developed LVP with blood perfusion, and 26% increase with crystalloid perfusion at a perfusion pressure of 80mmHg). Coronary reserve, estimated by reactive hyperemia, was independent of the perfusion pressure in both groups. Coronary reserve was small in the crystalloid-perfused hearts (<23%) and more than double the control value in the blood-perfused hearts. It is proposed that blood-perfused hearts are more suitable for physiological and pathophysiological studies.