Results of surgery for aortic regurgitation due to aortic valve prolapse.

The clinical, hemodynamic and pathological findings of 13 patients with aortic regurgitation due to aortic valve prolapse caused by advanced myxomatous degeneration were evaluated. Eleven patients showed a favorable outcome with no complications resulting from surgery. One patient died from aortic dissection, and another died suddenly from an unknown cause. Five patients had mitral valve prolapse as a complication. Ten patients (77%) had a long-standing history of hypertension. Twelve patients (92%) were male. None of the patients had the stigmata of Marfan's syndrome. All patients had marked myxomatous degeneration of the aortic valves without any inflammatory changes. Two patients showed microcalcification; 7 demonstrated moderate fibrosis. Five patients showed severe fragility of the cusps which appeared redundant, gelatinous and softened by degenerative changes. Myxomatous degeneration of the aortic valve is not rare, and, in fact, it may be one of the most common pathologic and clinical entities associated with pure aortic insufficiency.</p

A case of complete atrioventricular block due to malignant lymphoma.

A case of malignant lymphoma associated with complete heart block in a 30-year-old woman is reported. The patient progressively deteriorated despite temporary pacing and died 24 days after being admitted. Microscopic examination of the heart revealed marked infiltration by lymphoma cells in the atrioventricular node and the bundle of His. A diffuse lymphoma (large cell type, B cell) was diagnosed. This case is considered to be rare, since complete heart block was the first and only manifestation of the malignant lymphoma.</p

An Experimental Hemodynamic Study of the Pelvic Collateral Circulation

Iliac arteries were occluded in adult mongrel dogs to investigate pelvic hemodynamics. When the unilateral common iliac artery was occluded, the blood flow making a &#34;stopover&#34; within the pelvis was found to be significantly less than that of anatomical hemodynamics even under a resting condition. The blood flow decreased more significantly under exercise loading than under a resting condition, which demonstrates the presence of the &#34;steal&#34; phenomenon. This only occurs in the collateral circulation in the pelvis formed by two arterial systems which are related in a series. In deciding the appropriacy of reconstruction for the internal iliac artery in patients with aorto-iliac occlusive disease, this &#34;steal&#34; phenomenon should be kept in mind. In most cases, ischemic symptoms in pelvic organs may be due to a simple decrease of the blood flow supplied to the pelvis, or due to the &#34;steal&#34; phenomenon. If the pelvic region is in the state of ischemia owing to the &#34;steal&#34; phenomenon, reconstruction of the blood vessels flowing into the pelvis is not required.</p

Echocardiographic prediction of postoperative low cardiac output syndrome in patients with mitral stenosis.

Thirty-eight patients were operated on for mitral stenosis between March 1979 and September 1981. Thirty-six of them were examined as to their age, symptom duration, chest roentgenograms, electrocardiograms and echocardiograms to obtain various indices of left ventricular function. The usefulness of these indices as preoperative risk factors for predicting postoperative low cardiac output syndrome (LOS) was investigated. Cases which had values of ejection fraction, cardiac index, percent fiber shortening or mean velocity of circumferential fiber shortening less than 0.45, 2.0 l/min/m2, 25% and 0.80 circ/sec, respectively, in the preoperative echocardiographic examination were associated with a greater chance of postoperative LOS. Each of these factors was independently useful as a risk factor in cardiac surgery for mitral stenosis. Moreover, it was revealed that the combination of a preoperative percent fractional shortening (%FS) of less than 30% and a cardiac index smaller than 2.0 l/min/m2 indicated a strong predisposition toward postoperative LOS.</p

Experimental study on veno-venous extracorporeal membrane oxygenation for respiratory failure after lung transplantation.

Extracorporeal Membrane Oxygenation (ECMO) has been adopted as a means of strong respiratory support. In lung transplantation, reimplantation response is still a serious problem. It causes severe respiratory failure which is refractory to mechanical ventilation in some cases. The purpose of this study was to evaluate the effects of veno-venous ECMO after lung transplantation using a canine autotransplantation model. The autotransplantation model was created by keeping the left lung in a warm ischemic state for 2 h. After reperfusion, the right pulmonary artery was ligated. The following two groups were studied: Group 1, Control group, (no ECMO group) (n = 6). After reperfusion, both lungs were ventilated without ECMO. Group 2, ECMO group (n = 7). After reperfusion, veno-venous ECMO support was introduced with reduction of mechanical ventilation. In the no ECMO group, four of the animals died within 210 min after reperfusion. In the ECMO group, two of the animals died of severe pulmonary edema. Data of blood gas analyses (PaO2, PaCO2, and SvO2) after reperfusion were significantly better in the ECMO group, whereas there were no significant differences in both shunt fraction and pulmonary vascular resistance index. In this model with severe pulmonary edema induced by warm ischemia, veno-venous ECMO contributed to the improvement of hypoxemia and hypercapnia, but did not improve pulmonary hemodynamics.</p

Diagnosis of Rejection in the Allografted Rat Lung: Using Monoclonal Antibodies to T Cell Subsets for Immunologic Monitoring

Early diagnosis of rejection and timely immunosuppression are absolutely important in clinical lung transplantation. We studied surface markers of peripheral blood lymphocytes (PBL), graft infiltrating lymphocytes (GIF) and bronchoalveolar lavage fluid (BALF) in a rat using flow cytometric monitoring to diagnose rejection. Left lung transplantation was performed on Brown Norway (BN) rats and Lewis (LEW) rats in the following groups; Group 1: LEW-LEW (isograft), Group 2: BN-LEW (allograft; no immunosuppression), Group 3: BN-LEW (allograft; treated with Cyclosporine A at a dose of 15 mg/kg/day i.m.). In each group, rats were killed 3, 5, 7 days postoperatively (n = 6 on each day). Monoclonal antibodies investigated in this study were W3/25 (anti-helper T lymphocyte), OX8 (anti-suppressor/cytotoxic T lymphocyte), and OX39 (anti-interleukin 2 receptor). Histological classification of rejection in Group 2 showed vascular phase at 3 days, alveolar phase at 5 days, and destructive phase at 7 days, respectively. No evidence of rejection was found in Group 1 or 3. In Group 2, W3/25 positive cell proportion in GIL and BALF significantly decreased as the rejection progressed, but OX8 positive and OX39 positive cell proportion increases were significantly greater than in Groups 1 and 3 as the rejection progressed. These results lead us to speculate that the studies of T cell subsets in GIL and BALF lymphocytes are useful for diagnosis of rejection in lung transplantation.</p

Cellular immunocompetence in aortitis syndrome.

Cellular immunocompetence was investigated in 17 cases of aortitis syndrome (3 active, 14 inactive stage). Both the active and inactive groups demonstrated significantly lower interleukin-2 (IL-2) production than healthy volunteers. The active aortitis syndrome group produced significantly more interleukin-1 beta (IL-1 beta) than the inactive group. The proportion of CD11b+ CD8+ cells was significantly lower in the active aortitis syndrome group. Further, the proportions of CD11b- CD8+ cells and CD57+ CD16- cells in the aortitis syndrome patients were significantly higher than the healthy volunteers. These results suggest that there are intrinsic qualitative abnormalities in the T cells that produce IL-2 in aortitis syndrome. Pathogenesis of aortitis syndrome is considered as follows: during the active stage, diminished IL-2 production impairs differentiation and proliferation of suppressor T cells, thus creating abnormalities in the inhibitory functions of immunoregulation and promoting the proliferation of cytotoxic T and natural killer (NK) cells. This presumably initiates inflammation of the aorta and/or artery.</p

Correlation between the Layer of an Intimal Tear and the Progression of Aortic Dissection

Thoracic aortas isolated from dogs were evaluated to determine the correlation between the depth of an intimal tear and the progression of aortic dissection. Thoracic aortas obtained from 99 adult mongrel dogs were used. An intimal tear (aortic pocket) was created on the aortic wall and the aorta was connected in series to a closed circuit (150 mmHg/100 mmHg and 60 beats/min). The progression of the dissection was most notable in the aortic pocket prepared in the first one-third of the external media (87.5%). There was no correlation however between the width of the pocket and the progression of dissection. Examinations of samples from surgical patients have shown that dissection usually progresses at the same site. This has been attributed to the diseased media. Our results demonstrated that dissection occurred almost always at the same site without any medial changes suggesting that whether dissection develops or not likely depends upon whether the intimal tear reaches the first one-third of the external media or not

Long-term results of surgery for mitral regurgitation due to mitral valve prolapse: a comparison of valve replacement and annuloplasty.

Patients with mitral regurgitation (MR) due to mitral valve prolapse operated at the Second Department of Surgery, Okayama University Medical School, between 1976 and 1986 were divided into two groups. The first consisted of 20 patients who had mitral valve replacement (MVR) and the second 15 patients who had mitral annuloplasty (MAP). Long-term results of surgery, cardiac function, hemodynamic status, and surgical findings were compared between the two groups. Before surgery, there were no significant differences in patient's clinical status and cardiac function between the two groups. However, after surgery statistically significant differences emerged between the two groups in ejection fraction (EF), cardiac index (CI) and mean circumferential fiber shortening velocity (mVcf). Left ventricular pumping function and myocardial contractile force tended to decrease after surgery in the MVR group and to remain unchanged or even increase in the MAP group indicating that valve preservation procedures should be selected as often as possible for the patients involved in mitral valve prolapse.</p

Transplantation of the canine cadaver heart using a core-cooling technique.

We studied whether a cardiopulmonary bypass (CPB) and a core-cooling technique could resuscitate an arrested heart, and whether this procedure benefited canine cadaveric heart transplantation. Donor dogs were subjected to brain death by an intracranial balloon technique, and then, to cardiac arrest conducted by cutting off ventilatory support. In the control group (Group 1; n = 8), arrested hearts were flushed with cardioplegic solution and harvested thereafter without any resuscitation technique. In the experimental group (Group 2; n = 8), arrested hearts were once resuscitated using CPB, and then harvested using a core-cooling technique and cardioplegia. These hearts were transplanted orthotopically. Seven of eight recipients in Group 1 were weaned from CPB, and five of them finally became independent of dopamine administration. All recipients in Group 2 were successfully weaned from CPB, and also became dopamine free eventually. In Group 2, all post-transplantation hemodynamic values such as cardiac output during the period of dopamine administration were equivalent to those of post-brain death period. Chemical analysis of the serum and myocardial muscle demonstrated no difference between groups. We conclude that CPB combined with a core-cooling technique makes it possible to utilize an arrested heart as a donor organ for transplantation.</p