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Biomedical subjects

S Nawa

Publications and source records attributed to S Nawa.

At least 37 records · Page 2Linked to original sources
PubMed1993

Spontaneous secure reimplantation of a dislodged pacemaker electrode onto the right ventricular outflow tract, reestablishing a sufficient pacing condition.

A 62-year-old woman underwent cardiac pacemaker implantation for sick sinus syndrome with bradycardia, and the tip of an endocardial tined lead was positioned to the right ventricular apex. On the fifth postoperative day, an incomplete pacing failure, lasting about 10 min, was observed transiently on 24-h monitoring. This event, however, was not considered to be a clinical manifestation of the ensuing complication until the patient visited our pacemaker clinic 2 months postoperatively. At that time, a chest x-ray demonstrated that the electrode tip had migrated markedly to the right ventricular outflow tract (RVOT), but presented a sufficient pacing condition. The reimplantation site appeared to be very insecure for pacing, raising the potential risk of repeat dislodgement since the lead was not provided with a helix. At the second operation, performed to assess the problem, the ventricular excitation threshold measured at 1.3 V with a 0.5 ms pulse width. Furthermore, it was unexpectedly disclosed that the electrode tip was so tightly anchored at the site that it could not be withdrawn, eliminating the possibility of repeat dislodgment. Consequently, the entire original pacing system could be used as before and no further complications were observed. Although the situation encountered was very rare and seemed to be problematic, careful observation might be an alternative to surgical intervention even when a tined tip without helix has been used.

Electrodes↗
PubMed1993

Efficacy of percutaneous transluminal coronary recannalization for preservation of the post-infarct left ventricular regional wall motion: a trial of the evaluation by weighting coronary artery segments.

Efficacy of the percutaneous transluminal coronary recannalization (PTCR) therapy was evaluated by weighting infarct-related coronary artery segments in 28 consecutive patients with acute myocardial infarction. The study focused on the influences of the time interval from the onset of chest pain to PTCR (PTCR-Time) and on the post-infarct left ventricular regional wall motion in conjunction with the serum levels of GOT, LDH and CPK and with PTCR-Time. PTCR success rate was 84.0%, and re-occlusion rate was 4.0%. The thrombolysis in myocardial infarction grade 2, however, was observed in 7 (33.3%) of 21 cases with successful PTCR. There was no significant difference in PTCR-Time between the PTCR success and nonsuccess groups. Significant correlations were observed between the PTCR-Time and each peak value of standardized serum levels of LDH and CPK, and between the PTCR-Time and the post-infarct regional wall motion abnormality. There were also significant correlations between the standardized serum level of each of these three enzymes and the post-infarct regional wall motion abnormality. It was clearly demonstrated that the earlier the recannalization of the infarcted artery was achieved, the less extensive the myocardial damage in quantitative and qualitative aspects.

Adult↗
PubMed1993

Non-obstructive hypertrophic cardiomyopathy with mitral regurgitation requiring valve replacement.

Non-obstructive hypertrophic cardiomyopathy (HCM) is rarely associated with mitral regurgitation severe enough to require valve replacement. A 39-year-old man, previously diagnosed as having non-obstructive HCM with mitral regurgitation, developed atrial fibrillation with tachycardia and congestive heart failure. Echocardiography and cardiac catheterization, including left ventriculography, documented an unusual type of non-obstructive HCM with severe mitral regurgitation. The patient underwent successful mitral valve replacement.

Adult↗
PubMed1993

[A case of double-valve replacement in a patient with idiopathic thrombocytopenic purpura].

The aortic and mitral valve replacements were successfully performed in a case with idiopathic thrombocytopenic purpura. High-dose-gamma-globulin therapy and splenectomy had been tried. Neither of them, however could increase thrombocyte. After administration of Danazol treatment, thrombocytes moderately increased. With no expectation for further increase in thrombocytes, it was decided to carry out the open heart surgery with the aid of transfusion of thrombocyte-rich fresh plasma. Haemostasis after cardiopulmonary bypass required much longer time as 3 hours than in usual cases, but being successfully controlled. It has been reported that the effectiveness rate of the high-dose-gamma-globulin therapy ranges from 80 to 90%. Therefore this strategy will be the first choice in a case with ITP requiring open heart surgery. In the event that the strategies, including splenectomy, failed, other means such as Danazol therapy and transfusion of thrombocyte-rich fresh plasma should be considered.

Aortic Valve↗
PubMed1993

[Urgent mitral valve replacement for acute mitral regurgitation due to ruptured chordae tendineae in systemic lupus erythematousus].

We reported a successful surgical treatment of mitral regurgitation (MR) due to ruptured chordae tendineae in a 44-year-old man with systemic lupus erythematosus (SLE) who had received the steroid therapy. He had signs of acute congestive heart failure with severe pulmonary hypertension due to MR, and underwent urgent mitral valve replacement. The postoperative course was uneventful. When replacing valve in SLE, a careful manipulation should be taken because of friability of cardiovascular tissue. Patients are usually administered steroid agents, and the agents ought to be discontinued in perioperative period, but it seems to be better to resume as soon as possible. We conclude that the surgical treatment for valvular diseases should be considered, even in the patient with SLE.

Acute Disease↗
PubMed1993

[Descending thoracic aorto-aortic bypass grafting for coarctation of the aorta in an adult combined with a cerebral arterial aneurysm--a case report].

Coarctation of the aorta (CoA) in adults is often accompanied by hypertension, but CoA combined with a cerebral arterial aneurysm is rare. We performed successfully descending thoracic aorto-aortic bypass grafting for CoA in an adult who had a cerebral bleeding and a cerebral arterial aneurysm. The patient was a 46-year-old female who had the history of hypertension. She suddenly suffered from left hemiparesis due to cerebral bleeding, then a left middle cerebral arterial aneurysm and CoA were detected at the same time. Aortography showed that the internal diameter of the portion of the coarctation was 2.8 mm and the poststenotic dilatation was prominent. The peak systolic pressure gradient across the coarctation was 60 mmHg. We took the precedence of the surgical repair for CoA over that for the cerebral arterial aneurysm, because her cerebral arterial aneurysm was judged to have less risk to rupture from the viewpoint of its size and shape by neurosurgeons. We performed proximal descending thoracic aorto-distal descending thoracic aortic bypass grafting with a woven double velour graft of 16 mm in internal diameter and 9.5 cm in length. Intraoperative cerebrovascular hypertension can be avoided by this procedure. Furthermore the peak systolic pressure gradient has disappeared immediately after grafting. In general, the coarctectomy with direct end-to-end anastomosis is prevalent for CoA in adults. On the other hand, the descending thoracic aorto-aortic bypass grafting for CoA in adults has rarely been reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗
PubMed1992

Influences of ventricular pacing on hemodynamics, myocardial metabolism, and cardiac work efficiency: potential risks of rate-responsive ventricular pacing.

The influences of ventricular pacing at a rate of 70 beats/min (bpm) on the systemic and coronary hemodynamics, myocardial metabolism, and cardiac work efficiency were evaluated in five patients with bradycardia. The results were compared to those obtained in six normal subjects at rest. In order to elucidate the effects of a relatively high rate of ventricular pacing, cardiovascular and metabolic variables were also obtained at 120 bpm in the normal subjects. It was observed that the patients eventually benefited from ventricular pacing at a rate of 70 bpm and improved in systemic hemodynamics. Although coronary hemodynamics and myocardial metabolism were accelerated, the cardiac work efficiency was not improved. A pacing rate of 120 bpm in the normal subjects did not appear to accelerate systemic hemodynamics, but adverse accelerations of coronary hemodynamics and myocardial metabolism were observed, and the cardiac work efficiency was remarkably reduced as a result. Our observations indicated that the coronary reserve capacity was very important for ventricular pacing, and suggested that an undue increment of the pacing rate not only might be meaningless but also might induce ischemic angina. Therefore, we should be cautious in using a rate-responsive pacing mode, particularly in determination of the upper limit of pacing rates, although many benefits with this pacing mode have recently been advocated.

Adult↗
PubMed1992

[Report of three cases of emergency surgical salvage for acute pulmonary embolism].

Pulmonary embolism (PE) is one of the increasing diseases in Japan, which is aggravated rapidly and early diagnosis is necessary to improve its prognosis. We experienced three cases of successful surgical salvage. It is emphasized that the Doppler ultrasonic echocardiography plays important part in diagnosing PE early and noninvasively. Namely, it shows a appearance of acute cor pulmonale, and is usually able to guess the pulmonary artery pressure by using the simplified formula of Bernoulli's equation. We believe that the surgical pulmonary embolectomy under the cardiopulmonary bypass should be immediately considered in case of unsatisfactory conservative thrombolytic therapy.

Acute Disease↗
PubMed1992

[Effect of potassium canrenoate on serum magnesium levels after extracorporeal circulation].

Serum magnesium (Mg) levels were measured before and after operations involving extracorporeal circulation in thirty-five patients. Twenty patients were administered potassium canrenoate 200 mg/day from 2 days before operation to the 3rd postoperative day. Another 15 patients to whom there had been no administration of potassium canrenoate served as controls. We investigated the difference of serum Mg levels between the two groups. The serum Mg levels significantly decreased immediately after operations as compared to the values before surgery as from 1.9 +/- 0.2 to 1.5 +/- 0.2mEq/l (p less than 0.001) and from 1.8 +/- 0.2 to 1.4 +/- 0.2mEq/l (p less than 0.001) in the medicated and control groups, respectively. Serum Mg levels on the 2nd postoperative day recovered to within the normal range and it was significantly higher in the medicated group (1.7 +/- 0.2mEq/l versus 1.5 +/- 0.3mEq/l; p less than 0.05). Hypomagnesemia (Mg less than or equal to 1.2mEq/l) was found in seven patients (46.7%) in the control group and in two patients (10.0%) in the medicated group. Thus, there was a significant difference in the incidence of hypomagnesemia between the two groups (p less than 0.05). These results suggested that administration of potassium canrenoate is useful for keeping and improving serum Mg levels after extracorporeal circulation.

Adolescent↗
PubMed1990

[A case report of hyperosmolar hyperglycemic non-ketotic coma after aortic valve replacement].

A 56-year-old man without a past history of diabetes mellitus underwent aortic valve replacement. On the 8th postoperative day, the patient became confused with a peak blood glucose level of 600 mg/dl and peak serum osmolarity level of 411 mOsm/l, without ketotic urine. The diagnosis of hyperosmolar hyperglycemic non-ketotic coma (HHNKC) was made, and the patient was immediately treated with massive infusion of 0.45% saline water and continuous insulin administration, and the patient could completely recover. It is important to prevent and keep in mind the complication of HHNKC for the postoperative care after open heart surgery.

Aortic Valve↗
PubMed1990

[An adult case of congenital esophagobronchial fistula accompanied with bronchial branch of the vagal nerve].

A case of congenital esophagobronchial fistula in a 73-year-old woman was described. The patient had presented with repeated attacks of pulmonary infection from her childhood and had a several years history of recurrent cough after eating or drinking. Preoperative examinations including esophagogram by barium swallow revealed existence of a fistula between middle thoracic esophagus and right B6 bronchus. The fistula was recognized as Type II of Braimbridge and Keith's classification. The fistula was surgically removed with the atelectatic right lower lobe. Neither adhesion nor enlargement of lymph nodes was found in the surrounding tissues. Because the bronchial branch of vagus was found along the fistula, this lesion was strongly suggested of congenital origin. Histological observations of the resected fistula showed no chronic inflammatory changes, though muscular layers and transitional zone between squamous epithelium and bronchial epithelium were present. The differential diagnosis between the congenital and acquired types is sometimes very difficult. The existence of the bronchial branch of vagus along the fistula means that the fistula is a congenital type, definitely.

Aged↗
PubMed1989

Coarctation restenosis after isthmosubclavioplasty. A consideration on operative procedure and intraluminal balloon angioplasty.

We describe a case of a six-month-old boy in whom an aortic coarctation restenosis had developed three months after isthmosubclavioplasty. The restenosis was successfully relieved by means of intraluminal balloon angioplasty. At the isthmosubclavioplasty operation, extensive mobilization of the aorta to facilitate the anastomosis should be avoided. From anatomic and operative viewpoints, coarctation restenosis after the isthmosubclavioplasty operation was considered to be amenable to the intraluminal balloon angioplasty.

Angioplasty, Balloon↗
PubMed1989

Evaluation of conventional circulatory assist devices. Intraaortic balloon pumping, venoarterial bypass, and extracorporeal membrane oxygenation.

This study was undertaken to reveal the limitations and problems with the conventional mechanical circulatory assist devices by analyzing the results in 70 cases; intraaortic balloon pumping (IABP group, n = 42), venoarterial bypass pumping (VAB group, n = 18), and extracorporeal membrane oxygenation (ECMO group, n = 10). The IABP could significantly prevent the development of postoperative low cardiac output state, and the best survival rate (62 percent) was obtained in the coronary arterial disease group. In the VAB group, eight (44 percent) cases were weaned, and four (22 percent) cases survived. These conventional assist devices could, though with limitations, certainly support the circulation and/or provide a period for it to recover, otherwise bridging the patients to new methods. The early decision not only for initiation of mechanical assist devices but also for moving to more definite procedures will improve the results with such devices.

Assisted Circulation↗
PubMed1989

Evaluation of the left ventricular reserve by dynamic exercise echocardiography after surgery for valvular heart diseases.

Dynamic ergometer exercise in a supine position was applied to 64 patients more than 1 year after valvular heart surgery, and the left ventricular reserve was evaluated echocardiographically. The left ventricular reserve declined in the mitral stenosis-mitral valve replacement group, while it was better maintained in the mitral stenosis-mitral commissurotomy, aortic regurgitation and aortic stenosis groups. The patients were divided into 3 groups depending on whether the percentage increase during exercise of stroke index, an index of left ventricular pump function, increased, unchanged, or decreased. The percentage increase of mean velocity of circumferential fibre shortening (y) and that of left ventricular end-diastolic diameter (x) during exercise were plotted for each group. The increased group was isolated from the unchanged group by the line of y = -5.02x + 30.1; the unchanged group was isolated from the decreased group by that of y = -5.68x-10.0, and the increased and unchanged groups were clearly isolated from the decreased group by that of y = -6.86x-4.76. We conclude that dynamic ergometer exercise echocardiography is useful for evaluating the left ventricular reserve of postoperative patients with valvular heart disease. It was also thought that the subclinical state of cardiac failure can be effectively detected by the present method.

Adult↗
PubMed1989

Post-Fontan care based on hemodynamic characteristics, with special reference to the central venous pressure.

Changes in the hemodynamics of six patients having received Fontan-like operations were closely observed during the first 48 h after the operation. Catheterization studies and simultaneous angiocardiography were also performed before and after the operation. Hemodynamic derangement was particularly severe during the first 24 h postoperatively as indicated by a low cardiac output of less than 2.01/min/m2, which persisted in spite of very high central venous pressure. Furthermore, the central venous pressure needed to re-establish the circulation soon after the Fontan procedure significantly correlated with the angiocardiographically assessed preoperative size of distal pulmonary arteries. Accordingly, the preoperative evaluation of the distal pulmonary arterial size is very important, that provides a good guide-line for the degree of circulatory volume expansion necessary to elevate the central venous pressure and to sustain the circulation in the early postoperative period.

Adolescent↗
PubMed1989

Angiocardiographic quantitative evaluation of double-outlet right ventricle: special reference to the morphology of the common outflow tract.

Geometrical measurements of angiocardiograms of the common outflow tract (COT) of 13 patients were made to determine in which cases internal conduit repair was feasible, and under which conditions a patch enlargement of the COT was indicated. In the pulmonary stenosis (PS) group, the area of the narrowest cross-section of the COT was significantly smaller than that in the pulmonary hypertension (PH) group (p less than 0.025). In the PS group, the area was rarely sufficient to be shared by systemic and pulmonary circulation. Therefore, stenosis in the outflow tract to the pulmonary artery will occur if the intraventricular tunnel technique is applied, without patch enlargement of this portion, to patients with PS. On the contrary, the cross-sectional areas of the COT and pulmonary arteries were significantly larger in the PH group than in the PS group. Accordingly, the intracardiac conduit operation may be possible in such patients without a patch enlargement, even in young patients if other intracardiac conditions allow. Preoperative angiocardiographic evaluation of the COT is helpful in preoperatively selecting the proper operative procedure for this anomaly.

Angiocardiography↗
PubMed1989

Development of a new experimental model for total exclusion of the right heart without the aid of cardiopulmonary bypass.

A new experimental model for the total exclusion of the right heart was successfully developed in mongrel dogs without the use of cardiopulmonary bypass. A Y-shaped conduit was constructed with tube grafts spirally stented on the exterior (10 mm in diameter), and each upper limb of the conduit was provided with a 30F cannula. The foot of the conduit was anastomosed with the main pulmonary artery in an end-to-side way with a side clamp. After a closed atrioseptostomy was performed with a special knife of our design, the upper limbs of the graft were connected to the superior and inferior venae cavae by a cannulation method. The operative procedure was completed by tightening the occluding snares around the venae cavae and ligating the root of the pulmonary artery and azygos vein. Thus, without any use of the right atrium, venous blood from the venae cavae was totally diverted to the pulmonary circulation via the conduit, and only the coronary venous return was shunted to the left atrium. Five consecutive dogs tolerated the operative procedure. No pressure gradients were observed between the pulmonary arteries and venae cavae. The circulation with this model was able to be sufficiently sustained with mean pulmonary arterial pressures of about 25 mm Hg, and no significant changes were shown in the left ventricular pump function from the preoperative state. However, the decrease in the mean pulmonary artery pressure to 20 mm Hg resulted in severe circulatory failure, and two of the five dogs succumbed to this condition. Our new model will be useful for studying the hemodynamic characteristics of the circulation after operations that result in total exclusion of the right heart.

Animals↗