Ionescu-Shiley pericardial xenograft valve: Hemodynamic evaluation and early clinical follow-up of 326 patients

Dissatisfaction with the hemodynamic characteristics of available porcine valves prompted a clinical trial of the Ionescu-Shiley percardial xenograft (ISPX) valve. Three hundred fifty-six ISPX valves were implanted consecutively in 326 patients. Operative mortality was 2.6% (2/75) for aortic valve replacement alone and 7.7% (12/155) for aortic valve replacements that included reoperations and combined procedures such as mitral commissurotomy, annuloplasty, and coronary artery bypass. Operative mortality for all patients who underwent mitral valve replacement was 9.5% (14/147). The mean peak systolic gradient pressure in the aortic position was 5.4 mm Hg overall and 4.27 mm Hg with the size 19 mm valve. There were no embolic episodes in patients who received the ISPX valve in the aortic position. The available data indicate that the rate of peripheral embolism with the ISPX valve compares favorably with that of porcine valves. Considering its hemodynamic advantage, if the longterm durability of the full-orifice Ionescu-Shiley pericardial xenograft valve continues to be confirmed by follow-up studies, it is our opinion that it is the biologic valve of choice.     

Echocardiographic assessment of the Ionescu-Shiley pericardial xenograft in the aortic position

Echocardiograms of 30 patients with a normally functioning Ionescu-Shiley pericardial xenograft valve in the aortic position were analyzed to delineate the ultrasonic patterns produced by this bioprosthesis. The pericardial leaflets were recorded as thin, discrete echoes that were similar in configuration to the native aortic valve. Maximum systolic excursion of the anterior and posterior leaflets was 19 +/- 0.22 mm (standard deviation.) The presence of multiple echoes produced by the titanium frame was the major technical limitation to echocardiographic imaging of valve motion.     

Left ventricular function early after aortic valve replacement for aortic regurgitation: Assessment by gated radionuclide ventriculography

This study characterizes left ventricular performance early after aortic valve replacement for severe isolated aortic regurgitation. Gated radionuclide ventriculography studies in 13 patients showed that left ventricular end-diastolic volume was reduced after surgery and that ejection fraction dropped significantly. Despite the fall in ejection fraction, the postoperative cardiac index was significantly greater than the preoperative value. Radionuclide ventriculography is a useful and reliable means of noninvasively assessing left ventricular function soon after aortic valve replacement for aortic regurgitation.     

DIASTOLIC OPENING OF THE AORTIC VALVE (AV) IN A CASE OF AORTIC INSUFFICIENCY DUE TO AV FENESTRATION

A patient with severe aortic insufficiency due to fenestration of the non-coronary aortic valve leaflet is described. A preoperative echocardiogram demonstrated early closure of the mitral valve and early diastolic separation of the aortic valve leaflets. These findings disappeared after partial surgical correction and subsequent hemodynamic improvement. Premature opening of the aortic valve is common in severe aortic insufficiency.     

Replacement of the Aortic and Mitral Valves Using the Starr-Edwards Ball-Valve Prosthesis: A Report of 50 Cases

The aortic and mitral valves were replaced in 50 patients at the University of Alberta Hospital using the Starr-Edwards ball-valve prosthesis. The basis of the selection of 20 patients for isolated aortic valve replacement and 27 for mitral valve replacement using this type of prosthesis is presented, and the techniques of insertion of the aortic and mitral valve are described in detail. Of the 27 patients in whom the mitral valve was replaced by the Starr-Edwards prosthesis six died within 30 days of surgery and two after discharge from hospital at two and a half and four months, respectively. Left atrial thrombosis was the cause of death in four of these patients. In 20 patients in whom the aortic valve was replaced, four died in hospital and two died more than 30 days after returning home. Three of these six patients died from bleeding—the result of the use of anticoagulants. The difficulty in assessing whether or not anticoagulants are needed following replacement by a Starr-Edwards prosthesis is considered. It is felt, in our present state of knowledge, that anticoagulants should be used following mitral valve replacement but are probably not essential following replacement of the aortic valve. Two patients survived replacement of both aortic and mitral valves and have been followed up 18 months and seven months, respectively.     

Book Reviews

The findings in and experiences with 19 consecutive patients subjected to open mitral valve surgery are described. All patients underwent a right-heart catheterization. In order to exclude multivalvular heart disease, a left-heart catheterization was performed in 10 patients and angiographic studies of the aortic valve area in 12. Pulmonary function studies were performed on 11 patients. The FEV (0.75 sec.) and the MMFR were found to correlate well with existing pulmonary reserves.Fourteen of the 19 patients subjected to open mitral valve surgery survived the operation and have been followed up for three months to 2½ years. Four patients had a mitral valvuloplasty. Three of these four have deteriorated and will require a valvular replacement. Ten of 15 patients subjected to a mitral valve replacement are alive; five of these 10 have had signs and symptoms indicating peripheral embolization. Mitral valvuloplasty is preferable to a valvular replacement as far as embolic complications are concerned, while valvular replacements result in a more perfect and lasting hemodynamic repair. The high incidence of peripheral embolization following valvular replacements focuses attention on the need for improved mitral valve prostheses.     

Stentless Versus Stented Bioprosthetic Aortic Valves: A Systematic Review and Meta-Analysis of Controlled Trials

OBJECTIVE:: This meta-analysis sought to determine whether stentless bioprosthetic valves improve clinical and resource outcomes compared with stented valves in patients undergoing aortic valve replacement. METHODS:: A comprehensive search was undertaken to identify all randomized and nonrandomized controlled trials comparing stentless to stented bioprosthetic valves in patients undergoing aortic valve replacement available up to March 2008. The primary outcomes were clinical and resource outcomes in randomized controlled trial (RCT). Secondary outcomes clinical and resource outcomes in nonrandomized controlled trial (non-RCT). Odds ratios (OR), weighted mean differences (WMD), or standardized mean differences and their 95% confidence intervals (CI) were analyzed as appropriate. RESULTS:: Seventeen RCTs published in 23 articles involving 1317 patients, and 14 non-RCTs published in 18 articles involving 2485 patients were included in the meta-analysis. For the primary analysis of randomized trials, mortality for stentless versus stented valve groups did not differ at 30 days (OR 1.36, 95% CI 0.68-2.72), 1 year (OR 1.01, 95% CI 0.55-1.85), or 2 to 10 years follow-up (OR 0.82, 95% CI 0.50-1.33). Aggregate event rates for all-cause mortality at 30 days were 3.7% versus 2.9%, at 1 year were 5.5% versus 5.9% and at 2 to 10 years were 17% versus 19% for stentless versus stented valve groups, respectively. Stroke or neurologic complications did not differ between stentless (3.6%) and stented (4.0%) valve groups. Risk of prosthesis-patient mismatch was numerically lower in the stentless group (11.0% vs. 31.3%, OR 0.30, 95% CI 0.05-1.66), but this parameter was reported in few trials and did not reach statistical significance. Effective orifice area index was significantly greater for stentless aortic valve compared with stented valves at 30 days (WMD 0.12 cm/m), at 2 to 6 months (WMD 0.15 cm/m), and at 1 year (WMD 0.26 cm/m). Mean gradient at 1 month was significantly lower in the stentless valve group (WMD -6 mm Hg), at 2 to 6 month follow-up (WMD -4 mm Hg,), at 1 year follow-up (WMD -3 mm Hg) and up to 3 year follow-up (WMD -3 mm Hg) compared with the stented valve group. Although the left ventricular mass index was generally lower in the stentless group versus the stented valve group, the aggregate estimates of mean difference did not reach significance during any time period of follow-up (1 month, 2-6 months, 1 year, and 8 years). CONCLUSIONS:: Evidence from randomized trials shows that subcoronary stentless aortic valves improve hemodynamic parameters of effective orifice area index, mean gradient, and peak gradient over the short and long term. These improvements have not led to proven impact on patient morbidity, mortality, and resource-related outcomes; however, few trials reported on clinical outcomes beyond 1 year and definitive conclusions are not possible until sufficient evidence addresses longer-term effects.     

LOW PROFILE BIOPROSTHESIS FOR CARDIAC VALVE REPLACEMENT: EARLY CLINICAL RESULTS

Between May 1976 and April 1977, 100 patients underwent cardiac valve replacement with a unique low profile glutaraldehyde-treated porcine aortic xenograft. These patients were classified in four groups: Group I, 43 patients who underwent isolated mitral valve replacement (MVR); Group II, 27 patients who had isolated aortic valve replacement (AVR); Group III, 10 patients who had MVR and AVR; and Group IV, 20 patients who had MVR or AVR associated with other cardiac procedures. The operative mortality for Group I was 2.3% (1 of 43) and 15% (3 of 20) in Group IV. The total operative mortality was 4% (4 of 100) and the late mortality was 1.02% (1 of 96 survivors), who died apparently secondary to a cardiac arrhythmia. During a follow-up period extending for 16 months, thromboembolic complications occurred early in the postoperative period in 3% (3 of 100), one patient with neurological residual, and two patients with transient symptoms only. The embolic complications occurred only in Group I. Considering all patients in whom the mitral valves were replaced, the incidence of emboli was 4.9% (3 of 61). The 96 patients did not receive anticoagulant therapy. Reoperation was necessary in one patient because of periprosthetic leak. The incidence of endocarditis was 1.02% (1 of 96 survivors). We recommend anticoagulant therapy for eight to twelve weeks postoperatively in MVR patients after bioprosthetic insertion.     

Cardiac valve replacement in elderly patients.

Cardiac valve replacement in 65 consecutive elderly patients (aged 65 years and older) revealed that the indications for cardiac valve replacement in the elderly should be the same as those in the general population. These 65 patients represented 16% of the patients undergoing valve replacement. The mortality in the first 30 days after operation was 4.6% in the elderly group, compared with 0.9% in the group under 65 years of age. There were 26 significant but nonfatal early complications in the elderly patients, but their long-term functional status was excellent, most of the survivors ending up in either class I or class II of the New York Heart Association functional classification. The late mortality was 3.9% per patient year for aortic valve replacement and 15.1% for mitral with or without aortic valve replacement. The actuarial survival rates were 88% at 24 months and 55% at 54 months for the total elderly group, 86% at 36 months for those with aortic valve replacement, 85% at 24 months and 64% at 36 months for those with mitral valve replacement, 90% at 24 months and 77% at 42 months for the men, and 82% at 24 months and 68% at 42 months for the women. Aortic valve replacement was more common in the elderly than in the younger group because of the higher prevalence of congenital calcific aortic stenosis in the former, and this operation provided more gratifying results than mitral valve replacement in the elderly patients.     

Balloon dilatation of the aortic valve for inoperable aortic stenosis.

The place of balloon dilatation of the aortic valve in the treatment of calcific aortic stenosis is controversial. Thirty two patients (mean age 76) in whom valve replacement was contraindicated were followed up for three to 24 months (mean 8); 25 were in functional class III or IV according to the New York Heart Association''s classification. Major complications of the procedure occurred in four patients. Echocardiography and Doppler studies were performed before operation and before discharge in 28 patients, and the area of the valve was measured again six to 50 (mean 23) weeks after operation in 11 patients. The peak to peak aortic pressure gradient fell from a mean of 65 (SD 24) to 46 (20) mm Hg, but the area of the aortic valve, measured by Doppler echocardiography, in 18 patients showed a modest but significant increase, from 0.61 (0.16) to 0.74 (0.23) cm2. One month after dilatation, 29 patients were alive, of whom 17 had improved symptoms. Only two had lasting clinical benefit. Sixteen patients died, 12 of a cardiac cause. The estimated one year survival rate was 49%. Six patients underwent or required valve replacement because of persisting symptoms. In view of its limited long term efficacy balloon dilatation of the aortic valve should be used only for patients with severe symptoms whose life expectancy is limited by other disease or who are considered to be unsuitable for valve replacement. It may have a role in improving the condition of patients who present with cardiogenic shock or pulmonary oedema before valve replacement is undertaken.     

Is mitral valve repair safe procedure in elderly patients?

The aim of this randomized, prospective, study was to evaluate postoperative hospital mortality and morbidity after mitral valve repair by comparing two surgical techniques for resolving mitral valve insufficiency in elderly patients. In comparison were: mitral valve repair vs. mitral valve replacement in patients older than 70 years. In period from January 1st 2006 until August 30th 2009. Eighty patients with mitral valve disease, isolated or associated with other comorbidities, were scheduled for mitral valve repair or mitral valve replacement in our institution. Patients were randomized in two groups, one scheduled for mitral valve repair and another one for mitral valve replacement using the envelope method with random numbers. Results show no difference in hospital mortality and morbidity postoperatively in both groups. In group undergoing valve replacement we had one significant complication of ventricle rupture in emphatically calcified posterior part of mitral valve annulus. In conclusion we found no distinction in postoperative hospital mortality and morbidity after using one of two surgical techniques.     

Uncommon acquired Gerbode defect following extensive bicuspid aortic valve endocarditis

Gerbode defect is a rare type of left ventricle to right atrium shunt. It is usually congenital in origin, but acquired cases are also described, mainly following infective endocarditis, valve replacement, trauma or acute myocardial infarction. We report a case of a 50-year-old man who suffered an extensive and complex infective endocarditis involving a bicuspid aortic valve, the mitral-aortic intervalvular fibrosa and the anterior leaflet of the mitral valve. After dual valve replacement and annular reconstruction, a shunt between the left ventricle and the right atrium - Gerbode defect, and a severe leak of the mitral prosthesis were detected. Reintervention was performed with successful shunt closure with an autologous pericardial patch and paravalvular leak correction. No major complications occurred denying the immediate post-surgery period and the follow-up at the first year was uneventful.     

Mitral valve prolapse detected during hemodynamic studies

To estimate frequency of the posterior mitral valve leaflet prolapse in routinely performed left ventriculography, 1000 consecutive ventriculograms of the right anterior oblique projection were analyzed. A group of patients consisted of 511 women and 489 men at mean age 46,5 years. Clinical diagnosis of heart lesions, myocardial disease, pulmonary hypertension or arrhythmias were indications for hemodynamic studies. In the investigated group of patients, there were no patients with clinical diagnosis of the coronary artery disease. Prolapse of the posterior mitral valve leaflet was diagnosed in 59 patients. Idiopathic mitral valve prolapse was diagnosed in 10 patients. Prolapse of the posterior mitral valve leaflet was most frequent in atrial septal defect (16.6%), myocardial lesion (12.5%), and after mitral commissurotomy (8.9%). Posterior mitral valve leaflet prolapse is not a frequent anomaly in routinely performed left ventriculography. Relatively often occurrence of the mitral valve prolapse in atrial septal defect and only occasional in the aortic lesions and dilated cardiomyopathy seems to point out at a role of the left ventricle size in pathogenesis of this syndrome.     

Systemic and regional blood flows during graded treadmill exercise in dogs

The purpose of the study was to describe hemodynamic response and regional blood flows through various organs and tissues (microsphere technique) in dogs (n = 8), at rest and during mild (4 km/h, 13% slope; heart rate = 154 bpm), moderate (4 km/h, 26% slope; heart rate = 201 bpm), and severe (4 km/h, 39% slope; heart rate = 266 bpm) exercise on treadmill. Cardiac output (rest: 3.2 +/- 0.3; 39% slope: 10.2 +/- 1.3 l/min; mean +/- SE), systolic aortic pressure (rest: 122 +/- 4; 39% slope: 158 +/- 9 mm Hg), and left atrial pressure (rest: 5 +/- 0.7; 39% slope: 11.0 +/- 0.6 mm Hg) increased linearly with workload. On the contrary stroke volume increased from rest (35 +/- 2 ml) to mild (38 +/- 2 ml) and moderate (42 +/- 3 ml) exercise but decreased in response to the severe workload (38 +/- 5 ml). Regional blood flows across the brain, femoral bone, adrenal glands and temporalis muscle were not modified during exercise. On the contrary, a marked increase in regional blood flow was observed through the flexor and extensor muscles of the limb (X 5 to X 15), the muscles of the back (X 4) and the diaphragm (X 2.5). The small inconsistent increase in nutritional tongue blood flow probably underestimated the increased perfusion through arteriovenous shunts in the mucosa for heat-loss purposes. Myocardial blood flow increased in a linear fashion with work load in both ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic Response to Exercise After Beta-Adrenergic Blockade with Propranolol in Patients with Mitral Valve Obstruction

Propranolol (P) .13 mg./kg. was given to seven patients with mitral valve obstruction the changes in resting and exercise hemodynamics were followed by means of combined right and left heart catheterization. Changes were variable. At rest there was a decrease in heart rate of 10 beats/min. with no consistent change in stroke volume, cardiac output, left ventricular systolic (LVS) or left atrial (LA) pressure after P. Mean left ventricular end-diastolic (LVED) pressure was increased 3 mm., mean pulmonary artery (PA) pressure was increased 4 mm., and mean mitral valve gradient was reduced 3 mm. Hg by P. During exercise, mean LVS pressure was decreased 31 mm., mean LVED pressure increased 3 mm., mean LA pressure decreased 3 mm., and mean mitral valve gradient was reduced 5 mm. Hg after P. Mean exercise PA pressure was unchanged, cardiac output was reduced 0.9 1./min., and mean heart rate was reduced 37 beats/min., while stroke volume increased 3 ml./beat after P. Exercise pulmonary vascular resistance was increased from 6.1 to 8.2 units by P. Despite a slower heart rate, the diastolic filling period was not increased. P has no place in the treatment of the majority of patients with mitral stenosis because it further reduces cardiac performance below normal.     

DISCRETE MEMBRANOUS SUBAORTIC STENOSIS: POSTOPERATIVE REVERSION OF AORTIC VALVE ECHOCARDIOGRAM TO NORMAL

Clinical, hemodynamic, angiographic and echocardiographic findings in a patient with discrete membranous subaortic stenosis are presented. Echocardiography revealed evidence of a normal mitral valve and abnormal movement of the aortic valve with poor motion and fluttering of the anterior cusp. After a subvalvular membrane subjacent to the aortic valve cusp was excised, postoperative echocardiographic study showed normal movement of the aortic valve.     

Evaluation of digitalis in cardiac failure.

Ten patients in sinus rhythm with symptomatic cardiac failure participated in a study investigating the value of digitalis at rest and during dynamic exercise. A haemodynamic profile and left ventricular ejection fraction were measured before treatment, after intravenous ouabain, and after six weeks of maintenance treatment with digoxin. There was no significant change in the haemodynamic profile or in the left ventricular ejection fraction at rest after either glycoside. During exercise there was a significant reduction in left ventricular filling pressure from 39 +/- 3 mm Hg to 34 +/- 3 mm Hg (p less than 0.05) after ouabain and to 33 +/- 3 mm Hg (p less than 0.02) after digoxin. Cardiac index improved from 33 +/- 0.3 1/min/m2 to 4.0 +/- 0.4 l/min/m2 (p less than 0.01) after ouabain and to 3.8 +/- 0.4 l/min/m2 (p less than 0.01) after digoxin. During exercise stroke volume index and stroke work index also improved significantly with both glycosides. This was accompanied by an increase in left ventricular ejection fraction from 29 +/- 2% to 36 +/- 3% (p less than 0.05) after ouabain and digoxin. In this study both intravenous ouabain and maintenance treatment with oral digoxin exerted a modest positive inotropic effect in patients with cardiac failure in sinus rhythm. The haemodynamic benefit, however, was manifest only during exertion.     

Prolonged exercise induces left ventricular dysfunction in healthy subjects

To determine the effects of a moderately prolonged exercise on left ventricular systolic performance, 23 healthy male subjects, aged 18 to 51 yr (mean 37 yr) were studied. The subjects exercised first on a treadmill (brief exercise) and completed, on a separate day, a 20-km run. M-mode, two-dimensional, and Doppler echocardiography, as well as calibrated carotid pulse tracings, were obtained at rest and immediately on completion of both brief and prolonged exercise. Left ventricular systolic function was assessed by end-systolic stress-shortening relationships. Heart rate increased similarly after brief and prolonged exercise (+30%). Mean arterial pressure decreased from 99 +/- 7 to 92 +/- 8 mmHg (P less than 0.001) after prolonged exercise, but it remained unchanged after brief exercise. Left ventricular end-diastolic volume was decreased after prolonged exercise (130 +/- 23 vs. 147 +/- 18 ml at rest, P less than 0.01). Both ejection fraction and rate-adjusted mean velocity of fiber shortening decreased after prolonged exercise [from 67 +/- 5 to 60 +/- 6% (P less than 0.001) and from 1.12 +/- 0.2 to 0.91 +/- 0.2 cm/s (P less than 0.001), respectively] despite a lower circumferential end-systolic wall stress (133 +/- 23 vs. 152 +/- 20 g/cm2). The relationship between ejection fraction (or mean velocity of fiber shortening adjusted for heart rate) and end-systolic wall stress was displaced downward on race finish (P less than 0.05). These changes were independent of the changes in left ventricular end-diastolic volume and hence those in preload. The data suggest that moderately prolonged exercise may result in depressed left ventricular performance in healthy normal subjects.     

Blood flow conditions in the proximal pulmonary arteries and vena cavae: healthy children during upright cycling exercise

Diagnostic testing in patients with congenital heart disease is usually performed supine and at rest, conditions not representative of their typical hemodynamics. Upright exercise measurements of blood flow may prove valuable in the assessment of these patients, but data in normal subjects are first required. With the use of a 0.5-T open magnet, a magnetic resonance-compatible exercise cycle, and cine phase-contrast techniques, time-dependent blood flow velocities were measured in the right (RPA), left (LPA), and main (MPA) pulmonary arteries and superior (SVC) and inferior (IVC) vena cavae of 10 healthy 10- to 14-yr-old subjects. Measurements were made at seated rest and during upright cycling exercise (150% resting heart rate). Mean blood flow (l/min) and reverse flow index were computed from the velocity data. With exercise, RPA and LPA mean flow increased 2.0 +/- 0.5 to 3.7 +/- 0.7 (P < 0.05) and 1.6 +/- 0.4 to 2.9 +/- 0.8 (P < 0.05), respectively. Pulmonary reverse flow index (rest vs. exercise) decreased with exercise as follows: MPA: 0.014 +/- 0.012 vs. 0.006 +/- 0.006 [P = not significant (NS)], RPA: 0.005 +/- 0.004 vs. 0.000 +/- 0.000 (P < 0.05), and LPA: 0.041 +/- 0.019 vs. 0.014 +/- 0.016 (P < 0.05). SVC and IVC flow increased from 1.5 +/- 0.2 to 1.9 +/- 0.6 (P = NS) and 1.6 +/- 0.4 to 4.9 +/- 1.3 (P < 0.05), respectively. A 56/44% RPA/LPA flow distribution at both rest and during exercise suggests blood flow distribution is dominated by distal pulmonary resistance. Reverse flow in the MPA appears to originate solely from the LPA while the RPA is in relative isolation. During seated rest, the SVC-to-IVC venous return ratio is 50/50%. With light/moderate cycling exercise, IVC flow increases by threefold, whereas SVC remains essentially constant.     

Core temperature regulation of heart rate during exercise in humans

The relationship between two abnormalities of exercise physiology in chronic heart failure patients was investigated: chronotropic incompetence and decrease in core temperature. While at rest, 13 heart failure patients had an average sinus heart rate that was significantly higher than seven normals (92 +/- 13 vs. 82 +/- 10 min-1, P less than 0.05). However, during exercise, the trend of increase in sinus heart rate as a function of work load and O2 uptake was significantly greater in normals compared with heart failure (P less than 0.05), and the absolute increase in heart rate at 50 W of cycle ergometry was larger in normals compared with heart failure (38 +/- 17 vs. 22 +/- 13 min-1, P less than 0.05). Differences in core temperature regulation were also observed. In the normals, core temperature increased from 37.13 +/- 0.33 degrees C at rest to 37.37 +/- 0.31 degrees C at 50 W of exercise (P less than 0.01). In the heart failure patients, core temperature decreased from 36.99 +/- 0.33 degrees C at rest to 36.66 +/- 0.39 degrees C at 50 W of exercise (P less than 0.01). As expected, significant differences in hemodynamic and gas exchange variables were observed between the normals and the heart failure patients both at rest and during exercise. A multiple linear regression analysis was performed of heart rate changes as the dependent variable and thermoregulatory and hemodynamic changes as the independent variables to test for their influence on heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)