[Posterior mitral valve in the echocardiogram of mitral stenosis].
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Echocardiography↗
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Mitral valve operation via Port Access versus median sternotomy.
OBJECTIVE: The advantages and disadvantages of minimally invasive Port Access mitral valve operation have not been defined relative to standard median sternotomy. A study was therefore designed to delineate differences in outcome from mitral operation via Port Access versus sternotomy in comparable patients. METHODS: The records of 41 consecutive patients undergoing isolated mitral valve replacement (n = 14) or repair (n = 27) were examined. All operations were performed using cardioplegic arrest through either median sternotomy (n = 20) or a small right anterolateral thoracotomy using an endoaortic clamp and catheter system (Heartport, Redwood City, CA) to arrest and decompress the heart (Port Access, n = 21). RESULTS: Both groups were well matched for age, mitral pathology, ejection fraction, and comorbidity. except that Port Access patients were less likely to be female. Three patients had undergone previous cardiac operations. Surgical procedure time was longer for Port Access patients (384+/-80 vs. 263+/-41 min, P < 0.05). Port Access provided significantly smaller incision length (8+/-2 vs. 26+/-2 cm, P < 0.01) and similar or shorter hospital stay (6+/-4 vs. 7+/-3 days). Port Access provided excellent visualization of the mitral valve and subvalvular apparatus, generally better than sternotomy, to allow complex mitral valve repairs. The greatest advantage of Port Access mitral operation was that Port Access patients returned to normal activity more rapidly (4+/-2 vs. 9+/-1 weeks, P = 0.01) than did patients undergoing standard median sternotomy. CONCLUSIONS: By avoiding a sternotomy, Port Access mitral valve operation provided a smaller incision and a dramatically more rapid return to normal activity than did median sternotomy. Port Access cardioplegic arrest with the Heartport system allowed visualization of the mitral valve superior to median sternotomy and has become the standard approach at this institution.
Case-Control Studies↗
The mitral valve orifice method for noninvasive two-dimensional echo Doppler determinations of cardiac output.
We developed and validated a mitral valve orifice method for Doppler cardiac output determination. In 15 open-chest dogs, cardiac output was controlled and measured by a roller pump interposed between the right atrium and pulmonary artery as a right-heart bypass. Left heart flows were measured in the open-chest dog model by Doppler measurements at the mitral valve orifice and compared not only to volume flow measured by the roller pump, but to electromagnetic flow meters as well. The maximum mitral valve orifice area was measured off short-axis two-dimensional echocardiographic views by planimetry. The maximal orifice was then adjusted for its diastolic variation in size by calculating a ratio of mean-to-maximal mitral valve separation on a derived M-mode echocardiogram. Flow was sampled parallel to mitral valve inflow in a four-chamber plane. The multiplication of mean flow throughout the cardiac cycle by the mean mitral valve area after correction for diastolic size variation yielded a cardiac output determination that could be compared to the roller pump measurement. Fifty-two cardiac output determinations over roller pump values of 1-5 l/min yielded a high correlation between roller pump flows and Doppler (r = 0.97 +/- 0.23 l/min). Our study shows that the mitral valve orifice provides an accurate site for Doppler cardiac output measurements.
Animals↗
[Cesarean section in a patient with severe mitral stenosis after mitral valve replacement].
A 30-year-old woman with mitral stenosis after mitral valve replacement was scheduled for cesarean section at 28 weeks and 6 days of pregnancy. Cesarian section was decided at a conference of obstetrics, cardiac surgery, neonatology and anesthesiology. Anesthesia was successfully managed with epidural block and pulmonary arterial pressure monitoring. During operation, blood pressure was controlled by dopamine, milrinone and phenylephrine. Patient did not develop cardiac insufficiency perioperatively. Cardiac function deteriorated gradually and reoperation of mitral valve replacement was performed 2 months later.
Adult↗
Angiographic diagnosis of posterior mitral valve leaflet prolapse.
The left ventricular cineangiograms of 22 asymptomatic, apparently healthy male aviators without noninvasive (echocardiographic or auscultatory) evidence of mitral valve prolapse were reviewed and compared with those of 12 men with noninvasive evidence of mild mitral valve prolapse. The maximal protrusion of the posterior mitral valve leaflet superior and posterior to a line perpendicular to the long axis of the left ventricle at end-systole was measured from the right anterior oblique left ventricular cineangiogram by repeated observation of left ventricular inflow. The values were 7.5 +/- 1.6 mm in patients without mitral valve prolapse and 11.2 +/- 3.4 mm in patients with mitral valve prolapse (mean +/- 1 standard deviation). This measurement did not exceed 11 mm in any patient without prolapse. It is concluded that: 1) with meticulous attention to angiographic landmarks of the left ventricular inflow area, the limits of normal systolic posterior mitral leaflet motion can be defined; and 2) systolic motion outside these limits constitutes a quantitative criterion for the angiographic diagnosis of mitral valve prolapse.
Adult↗
The role of atrial contraction in mitral valve closure.
BACKGROUND AND AIM OF THE STUDY: Ovine mitral valve closure is associated with presystolic mitral annular reduction coincident with atrial contraction, which is abolished with ventricular pacing. Whether lack of properly timed atrial contraction influences mitral valve closure or competence, however, is not known. METHODS: Eight sheep underwent myocardial marker implantation on the left ventricle, mitral annulus (MA), and mitral leaflets. After 7-10 days, the animals were studied with biplane videofluoroscopy at baseline and during ventricular or atrioventricular (AV) sequential pacing. Valve closure was timed from end-diastole (ED) and defined as minimum distance between two leaflet edge markers. ED was defined as peak of ECG R wave, end-systole as peak negative left ventricular (LV) dP/dt, and end-isovolumic contraction (EIVC) as 83.5 ms after ED. Septal-lateral (S-L) annular diameter was defined as distance between two markers at the middle of the anterior and posterior annulus. Regurgitant volume (RV) was calculated as relative volume change between ED and EIVC. RESULTS: V-pacing was associated with delayed leaflet closure (65 +/- 5 versus 29 +/- 10 ms, p = 0.008); moreover, RV (4.1 +/- 0.5 versus 1.4 +/- 0.5 ml, p = 0.02), end-diastolic S-L diameter (2.87 +/- 0.10 versus 2.67 +/- 0.09 cm, p = 0.0005), and MA area (8.12 +/- 0.37 versus 7.26 +/- 0.31 cm2, p = 0.009) all increased. RV and leaflet and annular dynamics during AV-pacing were similar to baseline. CONCLUSION: V-pacing increased S-L MA diameter by only 8 +/- 1%, but this change was associated with delayed leaflet coaptation and a 16 +/- 1% regurgitant fraction. These findings provide direct evidence that a properly timed atrial contraction is functionally important for effective mitral leaflet closure.
Animals↗
Platelets, thromboembolism and mitral valve prolapse.
Cerebral and retinal ischemic events have been described in mitral valve prolapse. To determine whether platelets play a part in the pathogenesis of thromboembolism we studied 29 patients with mitral valve prolapse, including nine (group I) with thromboembolism (cerebral, retinal and deep venous), eight (group II) with transient visual obscurations and 12 (group III) with neither thromboembolism nor visual complaints, compared with 18 control patients and 38 normal subjects. Patients in groups I and II had increased platelet coagulant activities concerned with the initiation and early stages of intrinsic coagulation, and group I patients had an increased proportion of circulating platelet aggregates and platelets relatively insensitive top epinephrine in aggregation and secretion. The incidence of platelet coagulation hyperactivity in patients with mitral valve prolapse was 76% (100% in group I, 75% in group II, 58% in group III), compared with 6% in control patients. These results suggest that platelets play a role in the purported association of thromboembolism and mitral valve prolapse.
Adult↗
Mitral valve replacement in dilated canine hearts with chronic mitral regurgitation. Importance of the mitral subvalvular apparatus.
The importance of the mitral subvalvular apparatus in terms of left ventricular (LV) mechanics and energetic efficiency in the chronically dilated canine heart was assessed in nine dogs with surgically induced mitral regurgitation. Miniature radiopaque tantalum markers were implanted into the myocardium to measure LV volume. Biplane cinefluoroscopic images obtained 1 week and 3 months after creation of mitral regurgitation confirmed the presence of LV dilatation. Mitral valve replacement with preservation of all chordae tendineae was then performed. LV systolic function and derived energetics were then assessed during transient caval occlusion both before and after chordal division by using exteriorized snares. Global LV systolic mechanics, as assessed by the slopes of the end-systolic pressure volume (Ees) and end-systolic stress volume (Ms) relations, fell by 46% (11.7 +/- 2.8 versus 6.3 +/- 1.4 mm Hg/ml, p less than 0.001) and 33% (17.8 +/- 4.0 versus 12.0 +/- 5.1 kdyne/cm5, p = 0.0001), respectively, when the chordae were divided. Chordal severing also increased systolic LV wall stress or LV afterload. In terms of calculated myocardial energetics, the slopes of the stroke work-end-diastolic volume and pressure volume area-end-diastolic volume relations declined significantly by 20% (85 +/- 14 versus 68 +/- 16 mm Hg) and 11% (116 +/- 20 versus 104 +/- 20 mm Hg) after cutting the chordae, thereby indicating reduced external stroke work and mechanical energy generated at any given level of preload. Moreover, the efficiency of energy transfer from pressure volume area to external stroke work fell by 19% (p less than 0.001). Since effective systemic arterial elastance (Ea) did not change, the Ea/Ees ratio (index of ventriculoarterial [V-A] coupling) increased from 0.93 +/- 0.27 to 1.67 +/- 0.62 (p = 0.006). Therefore, chordal division in dilated dog hearts due to chronic mitral regurgitation resulted not only in deterioration of systolic LV mechanics but also deleterious changes in calculated LV energetics and efficiency due to exacerbated mismatch in V-A coupling between the left ventricle and the systemic arterial bed, unfavorable loading conditions, and exhaustion of preload reserve. These observations in the low-pressure, volume-overloaded heart due to chronic mitral regurgitation underscore the importance of the mitral subvalvular apparatus for optimal LV systolic performance and energetic efficiency.
Animals↗
Surgical treatment of oligosymptomatic mitral valve incompetence?.
OBJECTIVE: Despite improvements of the surgical technique in NYHA (III)-(IV) mitral valve incompetence (MVI) postoperative long-term results remain poor. As long-term results reflect primarily the ventricular function rather than the quality of the surgical technique the contractile performance of isolated papillary muscles obtained from patients undergoing mitral valve replacement for MVI (n = 25) was analysed in detail. METHODS: Muscle preparations (0.4 x 5.0 mm) obtained from left ventricular papillary muscles (NYHA (I), n = 4; NYHA (II), n = 7; NYHA (III), n = 8; NYHA (IV), n = 6) were loaded for intracellular calcium measurements with FURA-2, stretched to optimal length (Lmax) and electrically stimulated with frequencies ranging from 30 to 180 beats/min (b.p.m.) (10% above threshold, 37 degrees C, Krebs-Henseleit solution). Isometric force development and diastolic intracellular calcium (measured by the 'ratio method'; excitation light: wavelengths alternating 340 and 380 nm, frequency: 250 Hz) were simultaneously recorded as a function of the stimulation frequency. RESULTS: At 60 b.p.m. force development was significantly higher in NYHA (I) myocardium (21.3 +/- 2.8 mN/mm2) than in NYHA (III) myocardium (12.8 +/- 2.2 mN/mm2), (P < 0.0001). In NYHA (I) myocardium force rose with increasing stimulation frequency ('positive staircase'). In contrast the stimulation frequency associated with maximum force was shifted towards lower frequencies in NYHA (II)-(IV) myocardium ('negative staircase'). As compared with NYHA (I) myocardium diastolic intracellular calcium was significantly elevated at 150 b.p.m. in NYHA (II)-(IV) myocardium (P < 0.01). CONCLUSION: The data show, that severe impairment of contractile function ('negative staircase phenomenon', reduced force, elevated diastolic calcium) is present in MVI classified as NYHA (III)-(IV) that may explain the poor long-term results. Most interestingly the data argue for a significant impairment of myocardial function even in NYHA (II) MVI. The results suggest an early surgical treatment of mitral valve incompetence as long as the myocardial function is normal (NYHA (I)) as (1) a reduced perioperative risk, (2) improved long-term results, and (3) a higher probability for mitral valve repair (instead of replacement) may be expected in these early stages of mitral valve disease.
Biopsy, Needle↗
Association of osteopontin with calcification in human mitral valves.
BACKGROUND: Little is known about the long-standing inflammation leading to calcification within heart valves. Osteopontin, a phosphorylated glycoprotein, is present within atheromatous calcific plagues in response to vascular endothelial injury. The purpose of the study was to investigate whether osteopontin exists in calcific mitral valve leaflets in human beings, and to determine a link between chronic inflammation leading to mitral stenosis and the osteopontin status of mitral valvular tissue. MATERIALS AND METHODS: We reviewed the case histories of 17 patients who underwent mitral valve replacement therapy for mitral stenosis between 1995 and 1997 (8 men and 9 women, mean age 61 years). Hybrid mouse monoclonal immunoglobulin G1 antibodies were used for immunohistochemical detection of osteopontin in the acetone-fixed specimen. The control group consisted of normal mitral valve tissue from cardiomyopathy patients who underwent cardiac transplantation. RESULTS: A weak osteopontin immunoreactivity was present in apparently normal mitral valve tissue obtained from cardiomyopathy patients. All mitral stenosis patients had immunoreactivity (17/17) for osteopontin within calcific deposits of mitral valve tissue. The intensity of osteopontin activity had a strong association with increasing macrophage and calcium aggregations in the mitral valvular tissue. We found no correlation between osteopontin status and clinical features on the prognosis of calcific mitral stenosis. CONCLUSIONS: We conclude that osteopontin coexists with intimal macrophages in calcific human mitral valve tissue. Demonstration of such association between the presence of osteopontin and calcification in human mitral valves is consistent with the hypothesis that calcification in this tissue is, at least in part, an actively mediated phenomenon.
Aged↗
[Average-term effects of reparative surgery of the mitral valve].
The paper summarizes a personal experience at Harefield Hospital in surgical repair of the mitral valve. From Oct. 1976 to June 1978 among 43 consecutive mitral valve operations 38 reparative procedures were performed. The aetiology was rheumatic in 32 cases, degenerative (floppy valve) in 4; subacute bacterial endocarditis superimposed on a rheumatic valve in 1 and congenital in 1. The mitral valve was stenotic in 21 cases, incompetent in 5 and both stenotic and incompetent in 13. One patient died, whereas two had to be reoperated. At a postoperative symptomatic evaluation (mean follow up 25 months) 25 patients (71%) are asymptomatic; 9 (26%) are improved and 1 remains unchanged.
Adult↗
Mitral valve prolapse due to coronary artery disease.
Controversy exists concerning the etiologic role of coronary artery disease in the prolapsing mitral valve leaflet syndrome. A 35 year old man with progressive coronary artery disease is described. Auscultation before and after his first myocardial infarction revealed only a fourth heart sound; subsequently left ventricular cineangiography demonstrated normal anatomy and function of the mitral valve, despite extensive wall motion abnormalities. Six months later he experienced another myocardial infarction after which the typical mid-systolic click, late systolic murmur of mitral valve prolapse developed. A second left ventricular cineangiogram at this time revealed mid-systolic mitral valve prolapse and mitral regurgitation. This patient's course indicates that myocardial damage from coronary artery disease can cause mitral valve prolapse in patients with preexisting redundant mitral valve tissue.
Adult↗
Studies on the elimination of bilirubin pre-operatively in patients with mitral valve disease.
This study looked at the hypothesis that patients with mitral valve disease have a reduced capacity to eliminate bilirubin prior to surgery for valve implantation. Radiolabelled bilirubin was administered as a bolus and as a steady state i.v. infusion so that its incorporation into plasma bilirubin, and the latter's elimination after the load, could be measured. Patients with mitral valve disease (10) and aortic valve disease (10), in NYHA functional classes II-III, with total bilirubin concentration < 26 mumol.l-1, were studied. The plasma conjugated bilirubin increased significantly during infusion with radiolabelled bilirubin; radioactivity also increased after 3-5 min both in mitral and aortic valve diseased patients. After termination of the infusion the decrease in plasma-free bilirubin concentration followed an exponential decay curve with a rate constant of 0.0101 +/- 0.0013 (mean +/- SD) and 0.00419 +/- 0.00130 for patients with aortic valve disease and mitral valve disease (P < 0.05) respectively. The rate constant correlated significantly with cardiac index (r = 0.55) (P < 0.01), and inversely with bilirubin concentration (r = -0.57) (P < 0.01). Patients with advanced mitral valve disease and normal bilirubin concentration demonstrated normal uptake. However, conjugation of bilirubin in the liver, with a diminished ability to eliminate a bilirubin load, indicated a functional block in the elimination of conjugated bilirubin, most likely related to a reduced liver flow.
Aortic Valve Insufficiency↗
Late results of combined mitral valve replacement and coronary bypass surgery.
The incremental risk of coronary bypass surgery was analyzed in 718 patients undergoing mitral valve replacement between 1971 and 1983. Ninety-eight patients (14%) had significant coronary artery disease requiring coronary bypass surgery. In 70 of these patients, the origin of the mitral valve disease was nonischemic, whereas 28 patients had ischemic mitral regurgitation unsuitable for conservative valve surgery. There were six operative deaths (9%) and four perioperative myocardial infarctions (6%) after mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease. Operative mortality was related to low output cardiac failure before operation or perioperative myocardial infarction. Actuarial curves predict survival (+/- standard error) of 55 +/- 7% at 5 years and 43 +/- 8% at 10 years. Preoperative functional class was the only significant predictor of long-term survival in this group (p less than 0.05). The actuarial survival of the 620 patients without coronary artery disease who underwent mitral valve replacement alone was 63 +/- 3% at 10 years. This was significantly better than that of the 70 patients who underwent mitral valve replacement and coronary bypass surgery for nonischemic mitral valve disease (p less than 0.001). Conversely, 5 year survival of the 28 patients with ischemic mitral regurgitation was 43 +/- 10%. This confirms the negative detrimental effect of an ischemic origin of mitral valve disease on survival after mitral valve replacement and coronary bypass surgery (p less than 0.0001).
Adult↗
Comparison of open mitral commissurotomy with mitral valve replacement with or without chordal preservation in patients with mitral stenosis.
BACKGROUND: Percutaneous balloon mitral valvuloplasty and durable mitral prostheses have made the role of open mitral commissurotomy (OMC) uncertain. METHODS AND RESULTS: Results from the use of St Jude mitral valve replacement (SJMVR) were compared with those of the use of OMC in 312 consecutive patients with mitral stenosis between 1983 and the present. OMC and SJMVR patients were well matched for age, sex, and comorbidity except that SJMVR patients had more severe stenosis and were more likely to undergo concurrent aortic valve replacement. Compared with OMC, SJMVR without chordal preservation involved a longer pump time (158 +/- 81 versus 87 +/- 41 min, P < 0.05), more frequent in-hospital complications or death (57 of 219 [26%] versus 4 of 52 [8%], P < 0.01), and longer hospital stay (13 +/- 11 versus 10 +/- 6 days, P = 0.001). Preservation of chordae to at least 1 mitral valve leaflet decreased early morbidity and mortality rates of SJMVR to values comparable to those of OMC (3 of 41 [7%]). Survival was greater at 10 years for OMC versus SJMVR (86 +/- 5% versus 67 +/- 4%, P = 0.03). Ten-year freedom from cardiac events was not different between groups (49 +/- 9% for OMC versus 55 +/- 4% for SJMVR, P = 0.7). Freedom from subsequent mitral procedures at 10 years was better for SJMVR (96 +/- 2% versus 58 +/- 8%, P < 0.001). CONCLUSIONS: In the modern era, SJMVR offers significantly greater durability than does OMC. Chordal preservation at the time of SJMVR may reduce perioperative complications to levels comparable to those of OMC.
Adult↗
[Determining factors in mitral valve reconstructive surgery. Report of 150 cases].
150 patients had mitral valve repair for mitral valve incompetence. There were 57 males and 93 females with a mean age of 22 years. 60% of the patients were in Class II NYHA and 40% in Class III and IV. Type I was present in 18 patients, type II in 98 and type III in 34 cases. Mitral repair included correction of valve prolapse, valvular enlargement with pericardial patch and annuloplasty with semi-rigid ring in 128 cases and PTFE patch along the posterior leaflet in 12 cases. The perioperative mortality rate was 2.6%. All patients had early post-operative echocardiography. According to this, mitral regurgitation was absent or tiny in 135 patients, grade II in 10 cases and grade III in 2 cases. It was moderate or important in twelve patients. In the late post-operative period. All the others patients were reoperated upon for mitral dysfunction in a mean time of 37 months. The reason for reoperation was in the majority of the cases the recurrence of mitral regurgitation related to increase of valvular and sub valvular disease. The late mortality rate is 7%. Out of 126 reviewed survivors on the long run, 71 patients are asymptomatic in class I, 53 patients in class II and 2 patients in class III NYHA. The estimated mitral regurgitation by echography in those patients is absent or trivial in 96 cases. grade II in 29 cases and grade III in one case. Mitral valvuloplasty is the preferred procedure in mitral insufficiency surgical management. It is associated to a low early mortality and morbidity rate. Despite the need for reoperation in about 10% of the cases in the long follow-up, mitral repair offers a good quality of life without anticoagulant treatment.
Adult↗
[Experimental production of mitral valve and papillary muscle lesions by cervical vagus stimulation in rabbits].
Mitral valve and papillary muscle lesions were experimentally produced in rabbits by cervical vagal stimulation or compression of the abdominal aorta. The involvement induced the similar findings to mitral valve prolapse in human beings including mid-systolic clicks and a late systolic or holosystolic murmur. Extrasystoles were also common. Necropsies disclosed papillary muscle swelling, bleeding and edematous change in the mitral valve, swelling of the myocardial cells and interstitial fibrosis. Further, bacterial endocarditis was induced in such rabbits by injecting pseudomonas alkaligenes. Possible connection of experimentally-induced lesions of the mitral complex and mitral valve prolapse in human beings was discussed.
Animals↗
Randomized trial comparing partial versus complete chordal-sparing mitral valve replacement: effects on left ventricular volume and function.
OBJECTIVE: The merits of retaining the subvalvular apparatus during mitral valve replacement for chronic mitral regurgitation have been demonstrated in numerous retrospective clinical investigations but not in a randomized study. In this report we analyzed the early and late effects of complete versus partial chordal preservation on left ventricular mechanics. METHODS: Forty-seven patients undergoing isolated surgical correction of mitral insufficiency were prospectively randomized to either total or partial chordal-sparing mitral valve replacement. Complete data from 36 patients were available for analysis. Of these individuals, 15 had preservation of the posterior leaflet only (P-MVR group), and 21 had complete preservation of all chordal structures (C-MVR group). Echocardiography was performed preoperatively, at the time of discharge, and after 1 year to determine dimensions, wall stress, left ventricular mass, and ejection function. RESULTS: End-diastolic volume decreased in both groups initially but continued to decline only in the C-MVR cohort. Similarly, although end-systolic volume decreased over time with total chordal preservation, no notable changes were observed in the P-MVR group. In the C-MVR group, end-systolic stress decreased initially but rose slightly by 1 year. In contrast, end-systolic stress remained unchanged at discharge in the P-MVR group and increased at 1 year. In terms of systolic performance, ejection fraction declined after surgical intervention with partial chordal-sparing techniques and did not improve by 1 year. Ejection fraction returned to the preoperative level after an initial decrease in the C-MVR group. Finally, left ventricular mass was reduced in the C-MVR cohort versus no change in the P-MVR group. CONCLUSION: Complete retention of the mitral subvalvular apparatus during mitral valve replacement confers a significant early advantage by reducing left ventricular chamber size and systolic afterload compared with partial chordal preservation. Furthermore, left ventricular ejection performance continues to improve over time, probably because of more favorable left ventricular remodeling.
Adult↗