Biomedical subjects

M Komeda

Publications and source records attributed to M Komeda.

At least 91 records · Page 5Linked to original sources

PubMed1996

Improving methods of chordal sparing mitral valve replacement. Part I: A new, non-distorting isovolumic balloon preparation for the left ventricle with intact mitral subvalvular apparatus.

BACKGROUND AND AIMS OF THE STUDY: The conventional isovolumic preparation with a single balloon, although employed for many years, distorts the chordae tendineae of the intact mitral apparatus. MATERIAL AND METHODS: Anterior balloon (one balloon inserted via a slit in the anterior leaflet) and double balloon (two balloons through slits in both leaflets) methods were developed and compared to the conventional method and natural conditions (LV filled with saline, or 'gold standard') in six ex-vivo, non-beating porcine hearts. RESULTS: LV volumes measured by the double balloon, anterior balloon, and conventional techniques all correlated highly with natural conditions, but the conventional method had a lower correlation coefficient (r = 0.99, 0.98, p < 0.0001 and < 0.001; and 0.92 p < 0.01, respectively at a left ventricular (LV) pressure of 50 mmHg, while r = 1.00, 1.00, both p < 0.0001; and 0.92, p < 0.01, respectively at 70 mmHg). Epicardial echocardiography revealed that the double balloon technique filled the space behind the chordae while maintaining normal chordal geometry, but the anterior balloon alone did not (p < 0.001). Similarly, the conventional method did not fill the LV outflow tract (p < 0.001) and had a mitral annular shift toward the left atrium (p < 0.001). Photography of both leaflets showed that only the double balloon method maintained normal geometry as assessed by leaflet length ratio; the other methods produced distorted geometry compared to natural filling conditions. CONCLUSIONS: With an intact mitral valve, the double balloon method provides more precise LV pressure-volume measurements while preserving the normal geometry of the chordae tendineae and mitral annulus.

Animals↗

PubMed1996

Improving methods of chordal-sparing mitral valve replacement--Part II: Optimal tension for chordal resuspension.

BACKGROUND AND AIMS OF THE STUDY: Although chordal-sparing mitral valve replacement (MVR) is popular, the optimal tension for preserved or reattached chordae tendineae (CT) or for synthetic (ePTFE) CT is unknown. METHODS: Changes in left ventricular (LV) systolic and diastolic function in nine dogs with anterior CT preservation with different levels of end-diastolic chordal tension (0, 10, 20, 30, and 40 gm, measured by spring scale) were compared using an isovolumic double-balloon technique. RESULTS: LV function data at each level of tension were compared to control data using 0 gm of tension. Systolic function assessed as Emax (mmHg/ml) at 10, 20, 30, and 40 gm versus control was: 5.7 +/- 2.6/4.9 +/- 2.7, 4.7 +/- 2.2/4.7 +/- 2.7, 4.8 +/- 3.1/4.7 +/- 2.8, and 5.0 +/- 3.5/5.1 +/- 2.9; delta improvement from the control at 10 gm was larger than that at 20 gm (p < 0.05 by paired t-test). Diastolic function assessed as diastolic stiffness (Sd, mmHg/ml) at the same CT tensions versus control was: 0.56 +/- 0.23/0.56 +/- 0.34, 0.53 +/- 0.30/0.57 +/- 0.37, 0.56 +/- 0.39/0.52 +/- 0.38, and 0.60 +/- 0.36/0.58 +/- 0.39; delta Sd was smaller at 20 gm than at 30 gm (p = 0.05 by ANOVA). LV equilibrium volume (Veq, ml) was: 10.7 +/- 3.9/10.1 +/- 3.9, 9.6 +/- 3.4/9.9 +/- 3.8, 10.8 +/- 4.0/10.3 +/- 3.4, and 10.6 +/- 4.0/10.6 +/- 3.5; delta Veq was larger (i.e., more compliant chamber) at 10 gm than at 40 gm (p < 0.05 by rm-ANOVA). Arrhythmias precluding satisfactory measurements occurred in two dogs at 30 or 40 gm CT tension. CONCLUSIONS: With chordal tension exceeding 10 gm, which is barely palpable, there was no additional enhancement in LV systolic function compared to zero CT tension. Veq was largest at the lowest tension; LV diastolic function (assessed as Sd) deteriorated with tensions of 30 gm or higher. The optimal end-diastolic tension of preserved CT should enhance systolic LV performance without adversely affecting diastolic function; in this isovolumic model, minimal CT tension (10 gm) best met these goals. Excessive tension may negate the potential hemodynamic benefits of chordal preservation during mitral valve replacement.

Animals↗

PubMed1996

Improving methods of chordal-sparing mitral valve replacement--Part III: Optimal direction for artificial chordae.

BACKGROUND AND AIMS OF THE STUDY: The optimal direction to preserve artificial chordae tendineae (CT) during mitral valve replacement (MVR) is not known, especially in regard to the response to inotropic stimulation which simulates exercise conditions. METHODS: Using a non-distorting isovolumic balloon technique, we compared left ventricular (LV) systolic and diastolic mechanics in 11 dogs in a control state (no chordal sparing) and with four different methods of chordal preservation: posterior, anterior, oblique (anterior papillary muscle chordae directed anteriorly and others posteriorly, the direction which theoretically augments LV systolic twist), and counter-oblique (counter, chordae preserved in directions opposite to oblique). RESULTS: Before dobutamine, delta Emax from the control was: 0.32 +/- 0.82, 0.10 +/- 0.43, 0.64 +/- 1.07, and 0.51 +/- 0.78 (anterior, posterior, oblique, and counter method, respectively). With dobutamine (3 mg/kg/min), delta Emax (mmHg/ml) was: 0.41 +/- 1.21, -0.13 +/- 0.75, 0.59 +/- 0.82*, and -0.34 +/- 0.71. Before dobutamine, delta LV stiffness (Sd, mmHg/ml) was -0.01 +/- 0.09, -0.02 +/- 0.12, 0.02 +/- 0.10, and 0.01 +/- 0.12; with dobutamine it was 0.01 +/- 0.09, 0.00 +/- 0.15, 0.03 +/- 0.15, and -0.06 +/- 0.11. Similarly, before dobutamine delta LV equilibrium volume (Veq) was -1.2 +/- 3.8, -0.3 +/- 3.0, -0.7 +/- 2.7, and -0.2 +/- 3.5, whereas with dobutamine zeta eq was -0.1 +/- 1.1, -0.4 +/- 0.8, 0.6 +/- 1.7, and -0.4 +/- 1.1. (Mean +/- S.D.; *p = 0.005 posterior and counter by ANOVA; p = NS (< 0.06) versus counter and posterior by ANOVA). CONCLUSIONS: The oblique method enhanced systolic LV function both with and without dobutamine, while a tendency towards better diastolic LV function (Veq) was observed with dobutamine. The anterior method was next best in preserving systolic function, both with and without dobutamine. LV diastolic function tended to deteriorate with dobutamine in the posterior group. Systolic function with the counter method deteriorated with dobutamine. These results warrant further study in an ejecting model to investigate LV systolic and diastolic mechanics with the oblique method of CT preservation, including interactions with LV systolic twist and diastolic recoil.

Animals↗

PubMed1995

Left ventricular function, twist, and recoil after mitral valve replacement.

BACKGROUND: Preservation of the mitral subvalvular apparatus during mitral valve replacement (MVR) has become more popular, in part because of the clinically and experimentally demonstrated more optimal left ventricular (LV) performance after surgery; the mechanisms responsible for this beneficial influence, however, have not been clearly elucidated. METHODS AND RESULTS: Fourteen dogs underwent placement of 26 myocardial markers into the LV and septum. One week later, the animals were studied while awake, sedated, and atrially paced (120 beats per minute) both under baseline conditions and after inotropic stimulation (calcium). The animals then underwent MVR and were randomized into either chord-sparing (MVR-Intact) or chord-severing (MVR-Cut) techniques. Two weeks later, the animals were studied under the same conditions. LV systolic function was assessed by the slope of the end-systolic pressure-volume relation (Ees); early LV diastolic filling was analyzed by the pressure-time constant of relaxation (tau). The instantaneous longitudinal gradient of torsional deformation for the LV (twist) was also calculated, as were the changes in twist with respect to time during systole and early diastole (LV recoil). Intergroup comparison showed a trend toward increased contractility (Ees, P = .061, before versus after MVR), as well as faster relaxation for the MVR-Intact group. Concurrent analysis of LV systolic function and the rate of systolic twist revealed a significant inverse relation, which disappeared after MVR when the chordae were severed. CONCLUSIONS: These observations suggest that the mitral subvalvular apparatus acts as a modulator of LV systolic torsional deformation into LV pump (or ejection) performance.

Animals↗

PubMed1995

Exploring better methods to preserve the chordae tendineae during mitral valve replacement.

BACKGROUND: It is not known how best to resuspend the mitral chordae tendineae during mitral valve replacement to optimize postoperative left ventricular (LV) systolic and diastolic function. METHODS: Six different techniques to preserve the chordae during mitral valve replacement were compared in 12 dogs using a nondistorting isovolumic technique: conventional, all chordae severed; anterior, all chordae preserved anteriorly; partial, anterior papillary muscle chordae preserved anteriorly; posterior, all chordae preserved posteriorly; oblique, anterior papillary muscle chordae directed anteriorly and posterior papillary muscle chordae posteriorly; and counter, opposite of oblique chordal direction. Control measurements (no chordal tension) were recorded between each experimental condition. RESULTS: The oblique method tended to have the best LV systolic function versus the conventional method (Emax = 4.0 +/- 1.8 versus 3.3 +/- 1.2 mm Hg/mL [mean +/- standard deviation]; p = 0.08 by repeated-measures analysis of variance; physiologic intercept Ees100 = 20.3 +/- 8.6 mL [p < 0.05 versus control]), with no major change in LV diastolic stiffness. The posterior method had a lower Emax (3.3 +/- 1.2 mm Hg/mL) than the oblique method, but a similar Ees100 (20.8 +/-8.1 mL; p < 0.05 versus control) and the best diastolic LV performance (LV diastolic stiffness = 0.46 +/- 0.23 mm Hg/mL). The counter method also had good systolic function (Emax = 3.8 +/- 1.2 mm Hg/mL; Ees100 = 19.7 +/- 7.5 mL; p < 0.05 versus control), but had less favorable diastolic properties (0.65 +/- 0.37 mm Hg/mL; p < 0.05 by repeated-measures analysis of variance versus posterior). CONCLUSIONS: In this isovolumic preparation in normal canine hearts, the oblique method of chordal resuspension was associated with the best LV systolic function, whereas the counter technique impaired LV diastolic function. These preliminary results warrant further study in ejecting and failing hearts to determine conclusively which chordal orientation best preserves LV performance after mitral valve replacement.

Animals↗

PubMed1995

Infralabyrinthine approach to vestibular neurectomy in Menière's disease.

The infralabyrinthine approach to vestibular neurectomy was performed in 9 patients with unilateral Menière's disease. According to the AAOO (1972) criteria, 7 of 9 cases were graded as class B and the remaining 2 cases as class C. Otherwise, according to the AAO-HNS (1985) criteria, 6 patients who could be followed over 2 years were all graded as 'complete' at the vertigo control. The compensation of the spontaneous vestibular signs was rapid in the first 2 postoperative weeks, though an occasional imbalance on movement persisted even 3 years after the operation. No specific caloric reaction was elicited in any patient after warm or cold water irrigation of the operated side in any postoperative period. There have been no serious complications except a delayed facial palsy that appeared in one case one week after surgery. This approach offers access to the vestibular nerve with minimal risk and morbidity.

Adult↗

PubMed1994

"Concealed" rupture of the left ventricle: successful surgical repair.

A 70-year-old woman with a history of angina and hypertension presented with a large anterior infarct complicated by rupture and tamponade. Angiography showed triple-vessel disease and a large anteroapical aneurysm. Operative findings included extensive dissection of the septum and rupture of the right ventricular free wall. The patient survived the operation, which included replacement of the left ventricular free wall, extensive patching of the septum, and plication of the infarcted right ventricle.

Aged↗

PubMed1994

Pilot study of the efficacy of a thrombin inhibitor for use during cardiopulmonary bypass.

Heparin is normally used for anticoagulation during cardiopulmonary bypass (CPB), but its use is contraindicated in patients with a history of heparin-induced thrombocytopenia, heparin-provoked thrombosis, or both. Heparin therapy can also be ineffective due to heparin resistance. A short-acting, oligonucleotide-based thrombin inhibitor (thrombin aptamer) may potentially serve as a substitute for heparin in these and other clinical situations. We tested a novel thrombin aptamer in a canine CPB pilot study to determine its anticoagulant efficacy, the resultant changes in coagulation variables, and the aptamer's clearance mechanisms and pharmacokinetics. Seven dogs were studied initially: Four received varied doses of the aptamer (to establish the pharmacokinetic profile) and 3 received heparin. Subsequently, 4 other dogs underwent CPB, receiving a constant infusion of the aptamer before CPB (to characterize the baseline coagulation status), with partial CPB and hemodilution, during 60 minutes of total CPB, and, finally, after a 2-hour recovery period. At a 0.5 mg.kg-1.min-1 dose, the activated clotting time rose with aptamer infusion from 106 +/- 12 seconds to 187 +/- 8 seconds (+/- 1 standard deviation) (p = 0.014), increased further with hemodilution (to 259 +/- 41 seconds; p = 0.017), and was even more prolonged during total CPB (> 1,500 seconds; p < 0.001). This later increase in the activated clotting time paralleled a rise in the plasma concentration of the thrombin aptamer during total CPB, as determined by high-performance liquid chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Left atrial pressure-clamp servomechanism demonstrates LV suction in canine hearts with normal mitral valves.

A novel technique is presented to study suction of the in situ left ventricle in open-chest experimental animals without requiring cardiopulmonary bypass or disturbing the native mitral valvular apparatus. In 17 dogs, left ventricular pressure (LVP) and left atrial pressure (LAP) were measured, the left atrium was cannulated and connected to a servo pump, and LAP was controlled to a setpoint near 0 mmHg by withdrawing blood from the left atrium. Heart rate [103 +/- 17 (SD) min-1], peak pressure (100 +/- 13 mmHg), minimum pressure (1.4 +/- 0.8 mmHg), and maximum rate of change of pressure with respect to time during isovolumic contraction and relaxation (2,506 +/- 775 and -1,761 +/- 855 mmHg/s, respectively) were normal. Servo control of LAP was possible to +/- 1 mmHg. LV suction was demonstrated in each heart (mean negative LVP -2.3 +/- 1.1 mmHg; P < 0.0001). This new technique demonstrates that the left ventricle can generate negative diastolic suction pressures when examined in vivo and in situ with an undisturbed mitral valve and physiologically normal preload and afterload. This adds to a growing body of evidence that, under appropriate circumstances, the heart can suck blood into itself and thereby aid in its own filling.

Animals↗

PubMed1994

Glutamate-induced intracellular Ca2+ elevation in isolated spiral ganglion cells of the guinea pig cochlea.

Intracellular calcium concentrations ([Ca2+]i) in acutely isolated spiral ganglion cells (SGCs) of the guinea pig cochlea were measured using digital imaging microscopy and the Ca(2+)-sensitive fluorescence dye fura-2. L-glutamate increased [Ca2+]i in SGCs with neuritic processes but did not lead to an increase in [Ca2+]i in SGCs without neuritic processes. The depolarization induced by high K+ (150 mM) solution increased [Ca2+]i in both SGCs, with and without neuritic processes. The L-glutamate-induced [Ca2+]i elevation was abolished in the absence of extracellular Ca2+. We thus propose that the increase of [Ca2+]i during L-glutamate stimulation is mainly related to an influx of extracellular Ca2+. The excitatory amino acids, probably L-glutamate, may function as a neurotransmitter of the hair cell-afferent nerve synapse in the guinea pig cochlea.

Animals↗

PubMed1994

Late hemodynamic effects of the preserved papillary muscles during mitral valve replacement.

BACKGROUND: The late hemodynamic effects of preserving the papillary muscles during mitral valve replacement have not been evaluated. METHODS AND RESULTS: Sixteen patients who had chronic mitral regurgitation due to myxomatous degeneration were randomized to preservation (Pres group, n = 8) or no preservation (No Pres group, n = 8) of the chordae tendineae and papillary muscles during mitral valve replacement. Rest and exercise nuclear ventriculograms were performed early (3 months) and late (5 years) after surgery. Early after surgery, the No Pres group had lower ejection fractions and stroke work indexes (P < .05 by repeated-measures [rm] ANOVA) than the Pres group did at similar end-diastolic volume indexes. The No Pres group had similar cardiac indexes after exercise because heart rate increased (P < .005 by rm ANOVA). Late after surgery, ejection fraction was greater at similar end-diastolic volume indexes (P < .005 by rm ANCOVA), and preload recruitable stroke work indexes (P < .001 by rm ANCOVA) were better in the Pres group. CONCLUSIONS: Preserving chordal attachments enhanced the late hemodynamic recovery after mitral valve replacement for mitral regurgitation.

Chordae Tendineae↗

PubMed1994

Optimal flow rates for retrograde warm cardioplegia.

Retrograde delivery of warm blood cardioplegia may improve nutrient cardioplegic flow beyond coronary obstructions, but may not adequately perfuse the right ventricle and the posterior left ventricle. To determine the optimal flow rate for warm retrograde cardioplegia, we assessed 62 patients undergoing elective coronary artery bypass in two studies. In the low flow study, administration of 50 ml/min (n = 9), 75 ml/min (n = 11), or 100 ml/min (n = 7) was associated with high lactate production and oxygen extraction during cardioplegic administration. At 50 minutes of cardioplegic arrest, the coronary venous effluent pH was low in all groups. In the high flow study, 30 patients all received flow rates of 100, 200, and 300 ml/min in randomized order during the crossclamp period. In addition, five patients received cardioplegia at a rate of 500 ml/min for the duration of the crossclamp period. Administration of 200 ml/min or higher minimized lactate production and maintained coronary venous pH within the physiologic range, but flows of 300 ml/min or higher did not increase oxygen use or reduce lactate or acid production. Patients in the low flow groups had significantly greater myocardial lactate release during cardioplegic infusion and after removal of the crossclamp than the high flow group. Warm retrograde cardioplegia should be delivered at flow rates of at least 200 ml/min during elective coronary artery bypass operations.

Adult↗

PubMed1993

Surgical treatment of postinfarction false aneurysm of the left ventricle.

Twelve patients underwent surgery for repair of false aneurysms of the left ventricle. The mean interval between the myocardial infarction and the diagnosis was 19 months (range 2 to 80 months). Congestive heart failure was the most common clinical presentation. Most patients had three-vessel coronary artery disease. The false aneurysm was posterior in 10 patients and anterior in two. Three patients with posterior aneurysm had severe mitral regurgitation. Repair was accomplished by resection of the false aneurysm and primary closure of the defect in four patients and by closure with a patch in eight. Nine patients also had coronary artery bypass. Mitral valve replacement was performed in three patients who had severe mitral regurgitation before the operation and in one patient who had severe mitral regurgitation after repair of the false aneurysm and could not be weaned from cardiopulmonary bypass. There were three operative deaths and one additional death after 2 months. All deaths occurred in patients who had mitral valve replacement. Eight patients survived the operation and remained well after a mean follow-up period of 62 months. Patients with false aneurysms of the left ventricle do well after surgical repair, except when concomitant mitral valve replacement is necessary.

Aged↗

PubMed1992

Operative risks and long-term results of operation for left ventricular aneurysm.

A review of 336 consecutive patients who underwent repair of left ventricular aneurysm from 1978 to 1989 disclosed that partial resection of the aneurysm and conventional closure of the ventriculotomy was performed in 281 patients, inverted T closure in 17, and endocardial patch in 38. These two latter techniques were developed in an attempt to restore normal left ventricular geometry. The operative mortality was 6.8% (23 patients). A stepwise logistic regression analysis of various preopeative clinical, hemodynamic, and angiographic variables revealed that left ventricular ejection fraction of 0.20 or less, age greater than 60 years, previous myocardial revascularization, lack of angina, and New York Heart Association functional class IV were independent predictors of operative mortality. The technique of repair was not a predictor of outcome, but when patients with poor left ventricular function were analyzed separately, the operative mortality was reduced from 12.5% to 6.5% when newer techniques were employed. Patients were followed up during a mean of 6.3 years. There have been 51 late deaths, 45 cardiac. Cox regression analysis indicated that poor left ventricular function and left main coronary artery stenosis were the only two predictors of late mortality. The actuarial survival at 10 years was 63% +/- 4%. Most patients (88%) are in New York Heart Association class I or II. These data indicate excellent long-term results after repair of left ventricular aneurysm. Newer techniques of repair are valuable in patients with poor left ventricular function.

Actuarial Analysis↗

PubMed1992

Alternative techniques of cardioplegia.

BACKGROUND: Although normothermic cardioplegia has been used with acceptable clinical results, no studies have previously been performed to determine the metabolic consequences of these various techniques of myocardial protection. Therefore, we have performed a randomized clinical trial to assess the effects of three cardioplegic techniques on myocardial metabolic recovery. METHODS AND RESULTS: Seventy-four patients undergoing coronary artery bypass graft surgery were randomized to receive normothermic antegrade blood cardioplegia (n = 25), normothermic retrograde blood cardioplegia (n = 23), or intermittent cold antegrade blood cardioplegia (n = 26). Myocardial oxygen consumption and lactate production, adenine nucleotides, and adenine nucleotide degradation products were measured during the operation, and cardiac creatine kinase isoenzyme (CK-MB) release was assessed after surgery. Warm antegrade cardioplegia maximized myocardial oxygen consumption during cardioplegic delivery. Postoperative CK-MB release was less after warm antegrade cardioplegia, but the difference was not statistically significant. Warm retrograde cardioplegia resulted in the greatest degree of anaerobic lactate production but did not increase morbidity and mortality. Perioperative myocardial infarctions and postoperative low-output syndrome were most common after cold cardioplegia, but this trend was not statistically significant. During warm antegrade cardioplegia, adenosine triphosphate (ATP) was metabolized to diffusible precursors, which were washed out during cardioplegic infusion. Warm retrograde cardioplegia produced a breakdown of ATP to inosine and hypoxanthine, small molecules that accumulated during the cross-clamp period and were not washed out, perhaps because of inadequate perfusion with retrograde delivery. During cold cardioplegia, ATP was dephosphorylated, and adenosine diphosphate, adenosine monophosphate, and adenosine accumulated. These compounds were not regenerated to ATP but were not washed out of myocytes because they are large anionic molecules. CONCLUSIONS: Intermittent cold cardioplegia inhibited mitochondrial function but prevented the degradation of adenine nucleotides. Warm antegrade cardioplegia had the greatest myocardial oxygen consumption, and warm retrograde cardioplegia had the greatest anaerobic lactate production. There were no differences in clinical outcomes between cardioplegic groups.

Adenosine Triphosphate↗

PubMed1990

Surgical repair of postinfarction ventricular septal defect.

Thirty-one patients underwent repair of postinfarction ventricular septal defect (VSD) from 1980 to 1989. All patients were in New York Heart Association functional class IV, and 15 of them were in cardiogenic shock when operated on. Coronary arteriography was performed in all patients before surgery: nine had one-vessel, 11 had two-vessel, and 11 had three-vessel disease. The VSD was anterior in 15 patients and posterior in 16. The operative technique evolved over the years from a fairly extensive infarctectomy and reconstruction of the septum and right and left ventricular walls with a double Dacron patch, to minimal or no infarctectomy and closure of the VSD by excluding the infarcted muscle from the left ventricular cavity. This is accomplished by suturing a single patch of bovine pericardium to healthy endocardium surrounding the infarcted muscle. The right ventricle is left intact. Overall mortality was 10%, with three operative deaths. All deaths occurred in patients in cardiogenic shock who had three-vessel coronary artery disease. Thus, the mortality for patients in shock was 20%, and the mortality for patients with three-vessel disease was 27%. The operative mortality for patients with posterior VSD was twice as high as in patients with anterior VSD. However, univariate analysis of various clinical, hemodynamic, and operative variables indicated that only three-vessel disease was predictive of operative mortality. Because the number of patients was small and the overall operative mortality relatively low, the results of this analysis may not be valid.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1989

Mitral valve annuloplasty: the effect of the type on left ventricular function.

This study was undertaken to determine whether rigid-ring annuloplasty and flexible-ring annuloplasty have the same effect on left ventricular function in patients with chronic mitral regurgitation secondary to degenerative disease of the mitral valve. Twenty-five patients who underwent isolated mitral valve repair and required annuloplasty were randomized into two groups: rigid-ring and flexible-ring annuloplasty. Left ventricular function was assessed by echocardiography and radionuclide angiography on the day before operation and 2 to 3 months later. Preoperative left ventricular function was similar in the two groups of patients. Postoperatively, left ventricular end-diastolic diameter and volume decreased significantly in both groups. The left ventricular end-systolic diameter and volume decreased significantly only in patients with a flexible annuloplasty ring. Left ventricular systolic function as assessed by pressure-volume relationships was significantly better in patients with a flexible ring (p less than 0.02 by analysis of covariance), and left ventricular performance measured by stroke volume-end-diastolic volume relationships was also better in these patients (p less than 0.05 by analysis of covariance). These data indicate that patients with a flexible annuloplasty ring have better left ventricular systolic function than patients with a rigid annuloplasty ring 2 to 3 months after mitral valve reconstruction for chronic mitral regurgitation secondary to degenerative disease of the mitral valve.

Adult↗

PubMed1989

[Report of a case of an atypical huge patent ductus arteriosus].

An atypical huge patent ductus arteriosus (PDA) associated with extreme pulmonary hypertension in a 6-month old female infant was reported. The left 3rd intercostal thoracotomy revealed huge PDA which has an appearance of pulmonary-ductus-descending aorta-trunk (PDDT) on the left side. The right side of the ductus continued to the aortic arch without demarcation between the ductus and the aorta. The median sternotomy clarified the ascending aorta, normal aortic arch, and main pulmonary artery. However, the top of the main pulmonary artery seemed to be fused with the aortic arch. The diagnosis of distal type of aortopulmonary window with wide communication was made and the total circulatory arrest with deep hypothermia and the intracavitary patching for separation of systemic and pulmonary blood flow seemed to be required for the complete repair. Total repair was decided to be postponed one week later and the chest was closed. The patient died of multi-organ failure originating from acute respiratory failure 23 days after exploratory thoracotomy without being repaired. Postmortem examination revealed a huge PDA freely communicating with the ascending aorta and the aortic arch. This is a report of an atypical huge PDA rarely seen and the conventional division or ligation is unfeasible. The circulatory arrest with deep hypothermia and intracavitary patching are obligatory for the surgical repair.

Ductus Arteriosus, Patent↗