[Evolution of surgical therapy in mitral stenosis].
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Catheterization↗
Biomedical subjects
M Morea
Publications and source records attributed to M Morea.
Stentless porcine and pericardial valve in aortic position.
Fifty-seven patients underwent aortic valve replacement with a stentless glutaraldehyde-fixed bioprosthesis; 27 received a porcine aortic valve and 30 had a bovine pericardial valve. Two groups of 30 patients each who had aortic valve replacement with a tilting-disc mechanical valve or a stented porcine bioprosthesis served as controls. There were no differences in sex, body surface area, valve lesion, and valve size among the four groups. Results were assessed on a Doppler-based determination of maximum velocity across the valve, aortic valve area, and degree of valve regurgitation. Velocity across the valve was significantly less with stentless pericardial valves than with stentless porcine valves, stented bioprostheses, and mechanical valves. Stentless valves had a significantly larger aortic valve area when compared with stented valves. Mild central aortic insufficiency was detected more often with stentless pericardial than with stentless porcine bioprostheses (p = 0.04). Stentless valves showed a higher incidence of complete atrioventricular block when compared with stented valves (p = 0.04). Long-term studies are now warranted to assess the durability of both types of stentless valves.
Adult↗
[Aortic dissection after aortic valve replacement: clinical and anatomic features].
BACKGROUND: Cardiac surgery has become a possible cause of ascending aortic dissection, particularly in patients who have undergone aortic valve replacement. METHODS: From January 1979 to December 1989, 134 patients with angiographic evidence of aortic dissection, were studied in the Haemodinamic Laboratory of the University of Turin. Twelve of these patients (7 men and 5 women), mean age 51.6 years, had been previously operated for aortic valve replacement. We evaluated incidence, clinical and anatomic features of ascending aortic dissection in this group. RESULTS: A dilated ascending aorta with a mean diameter of 4.92 cm. was noted in all these patients. The interval between valve replacement and diagnosis of aortic dissection was 57 months (range 1 day to 9 years). Reoperation was performed in 11 patients. Four intraoperative deaths occurred and 2 other patients died in the early post-operative period. Survival rate at 12 months was 50%. Our incidence of ascending aortic dissection after aortic valve replacement was 0.66% (10 patients out of 1499 operated for aortic valve replacement) and it is in agreement with reports from other Authors in literature. CONCLUSIONS: Replacement of the ascending aorta must be considered if an important dilatation of aortic root is found at time of aortic valve surgery. New efforts must be undertaken to identify patients at high risk for this complication because an elevated mortality rate is observed in reoperation for aortic dissection.
Adult↗
Bronchial responsiveness, oscillations of peak flow rate and symptoms in patients with mitral stenosis.
To better characterize airway hyperresponsiveness reported in cardiac patients questionnaire-recorded symptoms, bronchial responsiveness to methacholine (Mch) and to ultrasonically nebulized distilled water (UNDW), diurnal oscillations of peak expiratory flow (PEF) rate were evaluated in 32 patients with moderate mitral stenosis. Twenty patients were responsive to Mch (defined as provocative dose producing a 20% fall in forced expiratory volume in one second (PD20 FEV1) less than 3.2 mg) (geometric mean PD20 FEV1 851 +/- 154 micrograms SE). Only two patients showed a fall in FEV1 greater than 20% after UNDW challenge. Patients responsive to Mch challenge had lower FEV1 as percentage of vital capacity (FEV1/VC) (80 +/- 4.8 vs 83 +/- 3.8%, p less than 0.05), higher coefficient of variation of PEF (CV-PEF) (7.1 +/- 2.8 vs 5 +/- 2.4, p less than 0.05) and higher prevalence of wheeze (70 vs 25%, p less than 0.05) in comparison with patients non-responsive to Mch challenge. CV-PEF was significantly related to FEV1 (r = 0.347, p less than 0.05) and maximal expiratory flow at 50% expired volume (MEF50) (r = 0.405, p less than 0.05). The probability of responding to Mch bronchial challenge increased proportionally with the increase in CV-PEF and the decrease in FEV1, FEV1/VC and MEF50. Airway hyperresponsiveness of patients with mitral stenosis seems to be more similar to that reported in bronchitic than in asthmatic patients.
Adult↗
The role of plasma proteins in formation of obstructive protamine complexes.
Formation of complexes between heparin and protamine (in saline), or heparin, plasma proteins, and protamine (in plasma) was assessed by measurements of light transmission through different test solutions. To examine the formation of these complexes, 125I-labeled protamine was used. Addition of 125I-protamine to plasma or blood resulted in the sedimentation of 125I-protamine in the form of insoluble complexes. This complex formation was not affected by the presence of heparin, suggesting that protamine-plasma protein interaction may be primarily responsible for precipitation of 125I-protamine. To assess the capability of these complexes to obstruct the pulmonary circulation, an in vitro experimental model was developed. Citrated serum, plasma, blood, or saline were allowed to flow through a glass bead column with the help of a peristaltic pump. A pressure transducer positioned before the column allowed pressure measurements at a constant flow rate during the experiment. Mixing of protamine with plasma or blood prior to their passage through the glass bead column resulted in a significant increase in pressure suggesting that the column was being clogged with insoluble complexes. The increase in pressure occurred both in the presence and absence of heparin in plasma or blood. Under identical experimental conditions, the increase in pressure was insignificant when protamine was added to saline or serum regardless of whether heparin was present or absent. This was further confirmed by the use of 125I-protamine. These observations suggest that protamine forms insoluble complexes with certain plasma proteins. Based on these observations, it is hypothesized that following intravenous administration, protamine immediately forms complexes in circulating blood.(ABSTRACT TRUNCATED AT 250 WORDS)
Albumins↗
Risk factors of primary tissue failure within the 11th postoperative year in 217 patients with porcine bioprostheses.
From January 1979 to December 1979, 217 patients underwent valve replacement with porcine bioprostheses. The aim of this study has been to analyze possible host-related risk factors of primary tissue failure (PTF). Of the 207 survivors, 33 have been reoperated on because of prosthetic PTF. Actuarial freedom from PTF was 67.4% +/- 6.04% at 11 years. Several clinical and prosthetic variables have been analyzed as risk factors of PTF by stratification of the event-free actuarial rates with the tests of Mantel and Breslow, and then by introducing the significant variables into the Cox proportional hazards regression model. No significance was found for serum calcium and phosphorus levels, the calcium phosphorus product, normal sinus rhythm, and anticoagulant therapy. Age less than 40 years (40.3 +/- 15.9 vs 74.2 +/- 5.7; p = 0.0348 and p = 0.03) and mitral position (57.7 +/- 7.7 vs 90.9 +/- 5.2; p = 0.0124 and p = 0.0095) were significant predictors of PTF within the 11th postoperative year. Female gender approached statistical significance (63.7 +/- 7.9 vs 72.2 +/- 9.3; p = 0.2001 and p = 0.2043). Cox multivariate analysis showed that age less than 40 years (p = 0.008) and mitral position (p = 0.015) were independent determinants of PTF. In conclusion, we have not been able to confirm the influence of metabolic host factors on the occurrence of PTF, but young age (and not only pediatric age) and mitral position are significant predisposing factors.
Adult↗
Reduction of bronchial responsiveness to methacholine after mitral valve replacement.
Sixteen patients with mitral valve disease, in whom bronchial hyperresponsiveness to methacholine had been detected shortly before mitral valve replacement (MVR), were reevaluated 35 +/- 1.5 months after MVR. In 9/16 patients there was a significant (greater than 1.5 fold) increase in bronchial provocation dose of methacholine (PD20FEV1) after MVR. In the same patients there was a significant increase in vital capacity (from 69.6 +/- 5 to 75.8 +/- 5.2% of predicted, p less than 0.01), a significant decrease in cardiothoracic ratio and in radiologic score for lung edema (from 64.3 +/- 2.9 to 56 +/- 2.1, p less than 0.01 and from 38 +/- 4.5 to 14.6 +/- 2, p less than 0.001, respectively). In all the patients the increase in PD20FEV1 was not related to any change in spirometric values but it was related to the decrease in cardiothoracic index (r = 0.72, p less than 0.01) and in radiologic score for lung edema (r = 0.61, p less than 0.05) observed after cardiosurgery.
Bronchial Provocation Tests↗
[Is coronary angioplasty less costly than aortocoronary bypass?].
We retrospectively compared the cost-benefit ratio of coronary bypass grafting (CABG) and percutaneous coronary angioplasty (PTCA). Data were obtained on 40 CABG's and 40 PTCA's patients treated from 15/2/86 to 15/9/86. All patients had at last 1-year follow-up. PTCA and CABG groups had similar baseline clinical and angiographic criteria. We analyzed the following cost components: real estate, biomedical products, drugs, hospital charges, medical fees, cardiac and non-cardiac tests. Total cost of CABG exceeds that of PTCA by a factor of 1.64: 15,095,000 vs 9,201,346 Italian liras (ILit). Taking into account early and late medical and surgical complications, the factor decreases to 1.39: 15,746,500 vs 11,323,000 ILit. After 1 year of follow-up the factor decreases to 1.18: 16,613,500 vs 14,027,500 ILit. Our data show that the initial savings were reduced when complications and follow-up are considered, but PTCA's patients had shorter hospitalization, earlier return to work, lower psychosocial stress.
Angioplasty, Balloon, Coronary↗
Reoperations on heart valve prostheses: an analysis of operative risks and late results.
To evaluate risks and complications of reoperations on heart valve prostheses, we reviewed data on 183 patients who underwent reoperation because of prosthetic valve malfunction. The incremental effect of the redo procedure on hospital mortality and morbidity was studied by comparing primary and reoperative procedures and analyzing a series of possible predisposing factors. Late survival after first and second reoperations was computed, and possible determinants of late mortality were examined. Overall operative mortality was 8.7%; emergency operation (p = 0.0001), previous thromboembolism (p = 0.05), and advanced New York Heart Association functional class (p = 0.031) were the independent determinants. In a series of 1,355 patients having primary or secondary isolated valve replacement, the redo procedure was a significant risk factor in the univariate analysis (p = 0.025) but not in the multivariate analysis except for the subset of patients having mitral valve replacement (p = 0.052). The postoperative course was quite complicated, as evidenced by the long mean stay in the intensive care unit (mean stay, 3.8 days; longer than 2 days for 26% of the survivors). Nevertheless, postoperative complications were not significantly greater after a redo procedure than after a primary operation. Actuarial survival at 7 years was 57.3% +/- 8%. A comparison with a nonhomogeneous series from our institution did not demonstrate significant differences. In the subset of 16 patients having a second reoperation, late survival was 37.8% +/- 16% at 2 years. Advanced New York Heart Association class (p = 0.0001), double prosthetic valve dysfunction (p = 0.003), and any indication other than primary tissue failure (p = 0.06) were determinants of late mortality.(ABSTRACT TRUNCATED AT 250 WORDS)
Bioprosthesis↗
Morphological comparison of primary tissue failure (PTF) in porcine mitral and aortic bioprostheses in the same patient.
Clinical and pathological studies have not clearly demonstrated whether primary tissue failure (PTF) in porcine bioprostheses occurs more often in the mitral than in the aortic position. We have studied morphological alterations in both positions in the same individual in 15 patients (14 mitroaortic and 1 mitroaortotricuspid) reoperated upon for PTF. Bioprostheses explanted were photographed, radiographed and observed in transmitted polarizing light. All lesions received a score on the basis of morphological criteria. The creep of the stent was measured. Calcification was slightly heavier and the degree of creep was significantly greater in the mitral position. Tears, infiltration and pannus growth did not differ between the two positions. According to our study, there is no conclusive demonstration that bioprostheses degenerate earlier and more extensively in the mitral than in the aortic position.
Adult↗
In vitro evaluation of left ventricular assistance by cannulation of both femoral arteries.
The possibility of achieving effective mechanical ventricular assistance without the need for thoracotomy provides great clinical advantages. Two in vitro systems were used to assess left ventricular unloading by means of a small-diameter cannula inserted retrograde into the left ventricle by cannulation of the femoral artery. This cannula is connected to the inlet of a centrifugal blood pump (CP) that delivers the blood into the contralateral femoral artery. Steady-flow test circulation was used to pump fluid in a closed loop from a reservoir through the test cannula back into the reservoir. Pressure drops over cannulae with inner diameters of 4, 5, 6, 7, and 8 mm at flows of 2, 2.5, 3 L/min, against a pressure of 60, 80, 100, and 120 mmHg were calculated. A stationary pressure drop of 120 mmHg was measured at a flow of 3 L/min through a 100 cm cannula with an inner diameter of 6 mm. The second system was a pulsatile mock circulation composed of an atrial and an arterial reservoir linked by a pneumatic prosthetic ventricle. This system was coupled with a 100 cm cannula, 6.1 mm inner diameter, which was passed across the outflow valve of the pulsatile prosthetic ventricle and connected to a CP. Fluid was withdrawn from the ventricle and pumped back into the arterial reservoir. Pulsatile pressure drop over the cannula was measured at different CP flows for increasing systolic ventricular pressure; heart unloading was quantified as a function of CP flow under baseline and failing conditions of the prosthetic left ventricle model. At a constant CP flow the pressure drop over the cannula increased with the pulsatility inside the ventricle. The work of the prosthetic ventricle was reduced by more than 50% when the CP pump was set to 3 L/min; at the same flow setting, when the situation of a failing left ventricle was simulated, the CP was able to take over all the work of the prosthetic ventricle, establishing a stationary flow and a 25% higher mean aortic pressure. This approach to left ventricular assistance may have significant clinical relevance.
Assisted Circulation↗
The Omni design: evolution of a valve.
The Lillehei-Kaster prosthesis has been the subject of an engineering evolution to close the gap between engineering expectations and clinical performance. Advanced engineering development in response to users has narrowed this gap with the Omni design (Omniscience titanium and omnicarbon Pyrolite cages). Our studies on mitral Omniscience valves demonstrated that because anatomic and surgical variations, the anterior orientation was more forgiving than the posterior orientation, resulting in lower thrombotic complications (0.5% versus 3.3% patient-year). A subsequent thicker cuff was used to reduce the probability of anatomic interference and incomplete opening after cardiac recovery. Such findings were also incorporated in the Omnicarbon design. Five European centers implanted 354 patients (198 atrial valve replacement, 115 mitral valve replacement, and 41 double valve replacement with Omniscience valves between August 1984 and January 1986. No restrictive patient selection criteria were used. As of June 1987, 96% of the patients at risk were accounted for. Average follow-up was 1.7 +/- 0.4 years (range, 0.3 to 2.8 years), with a total follow-up of 555 years. There were no cases of structural failure or clinically significant hemolysis. Ninety-one percent of the patients improved one or more functional classes. Actuarial analysis of survival probability at 3 years is 92.5% for atrial valve replacement, 97.9% for mitral valve replacement, and 93.6% overall. There were no late deaths from valve thrombosis or thromboembolism. The actuarial freedom from all thromboembolic events (valve thrombosis, thromboembolism, and transient ischemia) is 97.8% at 2 1/2 years. Through close rapport between user surgeons and designers, the evolution of a valve with improved performance becomes a reality.
Actuarial Analysis↗
Protection of the heart by nifedipine cardioplegia during coronary artery surgery. A clinical-haemodynamic evaluation.
This study was undertaken to evaluate the myocardial preservation obtained by adding a Ca++ channel blocker, nifedipine, to cold potassium cardioplegia (4 mcg/Kg/L) in 24 patients undergoing coronary artery surgery. They were randomly divided into a treated (N) and a control (C) group. Significant differences between the two groups were noted in the cardiac arrest time (p less than 0.001), in the mechanical recovery mode (p less than 0.01) and in the inotropic support needed (p less than 0.01). Cardiac index increased significantly in group N but decreased in group C (p less than 0.01). Peripheral delta P/delta t and endocardial viability ratio (EVR) decreased in both groups. Coronary sinus and serum CK and CK-MB release were significantly lower in the treated group. ECG ischaemic changes occurred in 8 patients in group C but only in 1 case in group N (p less than 0.001). Arrhythmias occurred in 3 cases in group C (p less than 0.05). The incidence of perioperative myocardial infarction was not significant (2 cases in group C). These data suggest that nifedipine can protect the myocardial cell from ischaemic injury without depressing myocardial contractility or AV conduction.
Arrhythmias, Cardiac↗
Early thrombosis of a tricuspid valve prosthesis: two-dimensional echocardiographic demonstration.
We report on the case of a 35-year-old woman who had undergone tricuspid valve replacement with a Lillehei-Kaster prosthesis 7 weeks prior to admission to our institution. Real-time two-dimensional echocardiography indicated a large mass on the inferolateral surface of the right atrium, as well as a dense band of echoes on the atrial and ventricular surfaces of the prosthesis. The diagnosis, confirmed by angiography, was early, acute thrombosis of the tilting disc prosthesis. After an unsuccessful infusion of urokinase, the patient was taken to emergency surgery; at operation, a large thrombus was discovered on the inferolateral wall, and the valve replaced. The patient recovered uneventfully, with no recurrence of thrombosis. Our experience confirms that two-dimensional echocardiography is the preferred technique for identifying intracardiac thrombi, and that surgery with replacement of the prosthesis is the treatment of choice in cases such as this where the size and age of the clot contraindicate fibrinolytic treatment.
Journal Article↗
Fixed subaortic stenosis. Natural history of patients with mild obstruction and follow-up of operated patients.
Fifty-five patients, 37 men and 18 women, aged 8 to 71 years (median 23) with a diagnosis of fixed subaortic stenosis were seen in our institution between January 1966 and December 1983. Their subvalvular gradient varied between 0 and 135 mmHg. Aortic regurgitation was present in 44 patients. Thirty-eight patients were operated on. Sixteen patients had some additional cardiac disease, either congenital, or acquired. There were 2 early and 2 late deaths. Fifteen patients were studied again after surgery: the average peak-to-peak gradient has decreased from 88 +/- 28 to 19 +/- 16 mmHg and is zero in 5. No patient has needed a reoperation, so far. Of the 17 non-operated patients, 13 had a gradient of less than 50 mmHg; they are all in Class I-II after 1-5 years. The gradient has increased to 70 mmHg in 1 of the 4 recatheterised cases. Four patients have died, 2 suddenly, 2 of congestive heart failure. They all had a gradient of 55 mmHg or more. In conclusion, in asymptomatic patients of a somewhat "older" age, with a high prevalence of a discrete form of subaortic stenosis, an operation can be deferred if the pressure gradient is less than 50 mmHg, and there are no associated lesions. Identification of patients running the risk of sudden death remains elusive.
Adolescent↗
[Results of coronary artery bypass surgery. Surgical mortality, survival and follow-up functional state. Multivariate discriminant analysis of relative risk factors].
Clinical results of coronary artery bypass surgery, have been evaluated by analyzing operative mortality, late survival, late functional results and their related risk factors. Four hundred and thirty-seven consecutive patients who underwent coronary artery bypass surgery between January, 1979, and December, 1983, were the clinical material of this study. The gender of patients was male in 89% of the cases; age ranged from 34 to 78 years with a mean of 54.8 +/- 8.2 (SD). Patients with combined surgical procedures were excluded. Follow-up averaged 55.7 months; 404 survivors have been contacted (97% of the total study population, if operative and late deaths are added); 218 patients underwent a control exercise test; postoperative employment status was determined for 242 individuals. The operative mortality was 5.49% (24 patients). Death was due to cardiac causes in 75% of the cases. The overall actuarial survival rate was 85 +/- 1.9% after 5 years and 83.4 +/- 2.2% after 7 years. When non-cardiac related deaths were excluded the actuarial rates were 88 +/- 1.7% and 87.2 +/- 1.9% after 5 and 7 years respectively. Actuarial freedom from all ischemic events (cardiac related death, late myocardial infarction or recurrence of angina) was 66.1 after five years, and was 70.2% if operative deaths were excluded. Actuarial freedom from recurrence of angina for patients alive at follow-up was 78.7% after five years, actuarial freedom from myocardial infarction was 93.5%. The mortality hazard showed a diphasic response, being higher perioperatively and constant in the following 5 years of follow-up. All ischemic events, both singularly and together, showed an accelerated rate of occurrence at the first and after the fifth postoperative year, the slope of the curve being quite flat during the 1 to 5 year interval. The control exercise test was negative for 62.8% of the patients, positive for 33.5% and undeterminable in 3.7%. Employment status was postoperatively unaffected in 49.6% of the cases, while 27.3% of the patients retired: the remaining individuals had already retired before surgery. Statistical analysis (stepwise logistic regression) identified age (p = 0.002) and cross-clamp time (p = 0.016) as significant risk factors of operative mortality. The ejection fraction showed a value close to statistical significance (p = 0.06).(ABSTRACT TRUNCATED AT 400 WORDS)
Actuarial Analysis↗
[Results of aortocoronary bypass surgery: long-term clinical and functional evaluation of patients surviving the operation. Personal experience].
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Actuarial Analysis↗
Major sternal wound infection after open-heart surgery: a multivariate analysis of risk factors in 2,579 consecutive operative procedures.
From January, 1979, to December, 1984, at the Cardiac Surgery Department of the University of Torino Medical School, major sternal wound infections developed in 48 (1.86%) of 2,579 consecutive patients. These patients underwent open-heart procedures through a midline sternotomy and survived long enough for infection to appear. Possible risk factors were evaluated by means of a multivariate analysis. For the group of patients, we considered age, sex, hospital environment (different locations of our surgical facilities over the years), interval between hospital admission and operation, antibiotic prophylaxis, type of surgical procedure, elective or emergency surgical procedure, reoperation, duration of surgical procedures, duration of cardiopulmonary bypass, amount of blood transfused, postoperative blood loss, chest reexploration, rewiring of a sterile sternal dehiscence, duration of mechanical ventilation, and days of treatment in the intensive care unit. Univariate analysis indicated that age, sex, type and mode of surgical procedure, antibiotic prophylaxis, and duration of mechanical ventilation were not significantly associated with wound infection. For all other predisposing factors, a p value of less than .05 was demonstrated. These variables were entered in a multiple stepwise logistic regression. Six emerged as significant: hospital environment (p = .0001), interval between admission and surgery (p = .041), reoperation (p less than .0001), blood transfusions (p = .031), early chest reexploration (p less than .0001), and sternal rewiring (p less than .0001). Contamination of patients may occur before, during, and after operation, and any kind of reintervention may predispose to wound infection.
Cardiac Surgical Procedures↗