Biomedical subjects

J G Dumesnil

Publications and source records attributed to J G Dumesnil.

At least 19 recordsLinked to original sources

PubMed1995

Aortic valve replacement with pulmonary autograft in children and adults.

Aortic valve replacement with a conventional prosthesis is still flawed with complications, especially in children and young adults. Complex aortic root enlargement (Konno) is often needed because of small aortic diameter. The poor compliance with anticoagulation by teenagers and the risks associated with this made us look at alternative techniques. From November 1990 to June 1994, 70 patients were considered for pulmonary autografts in our institution; 64 underwent the procedure with one death and one failure to implant. Short-term results are excellent, with minimal gradient in 90% and minimal regurgitation in 96% of the patients. The long-term follow-up, hopefully, will confirm the superiority of this procedure over more conventional replacement.

Adolescent↗

PubMed1995

Medtronic Intact porcine bioprosthesis: clinical performance to seven years.

The clinical performance of the Medtronic Intact porcine bioprosthesis was evaluated in 1,084 patients (mean age 66.4 years, range 9 to 91 years) who had a total of 1,099 implantations between 1985 and 1992, inclusive. There were 709 aortic valve replacements, 297 mitral valve replacements, and 80 multiple valve replacements. Concomitant procedures were performed in 432 (39.3%). The age group distribution (years) was 35 or younger in 20 patients, 36 to 50 in 64, 51 to 64 in 274, 65 to 69 in 225, 70 or older in 500. The total follow-up time was 2,741 patient-years (mean, 2.5 years) and was 97.5% complete. The early mortality rate was 7.1% and late mortality was 3.9% per patient-year. The overall patient survival at 7 years was 70% +/- 3%. The freedom from major thromboembolism was 94% +/- 1% at 7 years (p = not significant for valve positions). The freedom from reoperation at 7 years was 93% +/- 1%; freedom from valve-related mortality was 89% +/- 2%. The freedom from structural valve deterioration at 7 years was 97% +/- 1% (aortic valve replacement 97% +/- 1%; mitral valve replacement 97% +/- 2%). The freedom from structural valve deterioration among age groups was not different for the overall population, aortic valve replacement, or mitral valve replacement. Hemodynamic assessment revealed obstructive properties for aortic valve replacement sizes of 21 and 23 mm and for mitral valve replacement sizes of 25 and 27 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1992

Valve prosthesis hemodynamics and the problem of high transprosthetic pressure gradients.

Recent studies suggest that all prosthetic valves are at least mildly stenotic and may cause relatively high pressure gradients despite normal prosthesis function; such gradients could be due to a mismatch between prosthesis effective orifice area and patient's body size. In order to address this problem more directly, we derived, using a physiologic pulse duplicator system, the theoretical relations between transprosthetic pressure gradients and prosthesis effective orifice areas indexed for body surface area, assuming a normal resting cardiac index of 3.0 l/min m-2 and 10-50% increases in stroke volume such as may occur during maximal upright exercise. These exponential relations show that a small decrease in indexed effective orifice area produces a large increase in pressure gradient, and that the indexed effective orifice area should ideally be not less than 0.9-1.0 cm2/m2 for aortic prostheses and 1.3-1.5 cm2/m2 for mitral prostheses in order to minimize postoperative gradients. Thus, high postoperative gradients do not necessarily indicate intrinsic prosthesis dysfunction but may also be due to patient prosthesis mismatch. Intrinsic prosthetic performance is best assessed by comparing in vivo calculated effective orifice areas to in vitro measurements for same type and size of prosthesis. Patient prosthesis mismatch can be avoided by calculating before operation the projected indexed effective orifice area of the prosthesis being implanted.

Aortic Valve↗

PubMed1992

[Measurement of cardiac output by Doppler echocardiography at the 4 cardiac valves].

Many observers remain sceptical with regards to the utilization of Doppler-echocardiographic measurements of intracardiac outputs for the quantification of shunts and regurgitations. In this context, we evaluated the feasibility and validity of measuring output at the level of the four cardiac valves in a population of 35 normal subjects (24 M, 12 F) aged from 23 to 37 years (mean +/- SD = 28 +/- 4). Measurement of stroke volume and output using predetermined criteria was possible in the aortic position in 35 (100%) subjects, in the mitral position in 34 (97%), in the pulmonary position in 20 (57%) and in the tricuspid position in 10 (29%). In 14 subjects (40%), measurement was possible at 2 sites, in 14 (40%) at 3 sites and in 7 (20%) at 4 sites. Inability to measure output was most often due to poor visualization of valvular annulus. There are excellent correlations between aortic stroke volume on the one hand and the mitral (r = 0.97, SEE = 3.41 cc), pulmonary (r = 0.97, SEE = 3.69 cc) and tricuspid (r = 0.96, SEE = 2.77 cc) stroke volumes respectively on the other. These results suggest that reliable measurements of output are feasible in a majority of cases in the aortic and mitral positions but to a much more limited extent in the pulmonary and tricuspid positions; given the small SEE's, they should be useful to quantitate shunts and regurgitations, when feasible.

Adult↗

PubMed1991

Use of Valsalva maneuver to unmask left ventricular diastolic function abnormalities by Doppler echocardiography in patients with coronary artery disease or systemic hypertension.

It has been suggested that changes in left atrial pressure may mask or mimic left ventricular diastolic function abnormalities detected by Doppler echocardiography. The effect of the Valsalva maneuver on the transmitral flow velocity profile was therefore studied in 28 patients without evidence of coronary artery disease (group 1, mean age +/- standard deviation 50 +/- 8 years) and in 94 patients with evidence of coronary artery disease or systemic hypertension (group 2, mean age 54 +/- 10 years). At baseline, group 2 patients had higher peak late diastolic filling velocity (A), lower peak early (E) to late diastolic filling velocity (E/A) ratio and longer isovolumic relaxation time than group 1, whereas heart rate, E velocity and E deceleration time were similar in both groups. During Valsalva, both groups had similar increases in heart rate and similar decreases in E velocity but E/A ratio decreased significantly only in group 2 because of a lesser decrease in A velocity. The E/A ratio was greater than or equal to 1.0 both before and during Valsalva in all but 1 patient in group 1, whereas in group 2, 32 patients had E/A greater than or equal to 1.0 at rest and during Valsalva, 33 patients had E/A greater than or equal to 1.0 at rest but less than 1.0 both at rest and during Valsalva. Using group 1 as controls, prevalence, specificity and positive predictive value of E/A less than 1.0 in group 2 were 31, 100 and 100% at rest and 66, 96 and 98% during Valsalva.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Theoretical and practical differences between the Gorlin formula and the continuity equation for calculating aortic and mitral valve areas.

Although the Gorlin formula and the continuity equation are both used to calculate valvular areas in the clinical situation, there have been few comparisons of the 2 methods. Mathematically, it can be shown that both formulas are derived from similar hydrodynamic principles which basically give a measure of the physiologic or effective area occupied by flow. However, the Gorlin formula contains errors in formulation and incorporates a constant that purports to give a measure of the anatomic rather than of the effective area of the valve. If both formulas are applied to the same hemodynamic data from aortic and mitral bioprostheses studied in a pulse duplicator system, the Gorlin formula constantly yields results 1 to 2% higher than the continuity equation for aortic valves and 12 to 13% higher for mitral valves. For any given type and size of prosthesis, the areas calculated by either formula increase linearly in relation to increasing pressure and flow (up to 20% for aortic valves and up to 35% for mitral valves). It is concluded that the Gorlin formula and the continuity equation are both pressure- and flow-dependent and are primarily related to the effective area occupied by flow rather than to the anatomic area of the valve. The 2 methods yield consistently different results due to differences in mathematical formulation. Such factors are important to consider when interpreting valve area calculations clinically.

Aortic Valve↗

PubMed1991

Quantitative relationships between left ventricular ejection and wall thickening and geometry.

The quantitative relationships that exist between left ventricular (LV) wall shortening, wall thickening, and geometry during LV ejection are not well defined. We used a mathematical model to measure these parameters in 40 patients with various LV geometries studied by echocardiography. As opposed to wall shortening, the percent contribution of wall thickening to LV ejection (% delta Vh) was 25 +/- 2% in normal subjects; in all the patients, it varied from 18 to 45% and was inversely correlated (r = 0.94) to the midwall radius-to-wall thickness ratio (R/h) of the ventricle at end diastole. On the other hand, the ratio of the quantity of blood ejected per unit of LV wall volume magnitude of delta V/V omega magnitude of varied from 0.20 to 1.20 (normal subjects 0.83 +/- 0.11) and was directly correlated (r = 0.94) to R/h; using independent data in the literature, we also found a similar relationship (r = 0.80) between the ratio of quantity of blood ejected per unit of LV mass (magnitude of delta V/M omega magnitude of) and R/h. Patients with presumably abnormal myocardial function did not satisfy the relationship between magnitude of delta V/V omega magnitude of or magnitude of delta V/M omega magnitude of and R/h.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗

PubMed1990

Validation and applications of mitral prosthetic valvular areas calculated by Doppler echocardiography.

Doppler echocardiography is used in the noninvasive evaluation of mitral valve prostheses using parameters heretofore validated primarily for native valves. Accordingly, this study was designed to examine the validity and relative usefulness of valve gradient and area measurements in a group of 26 patients (17 women, 9 men, mean age 62 +/- 8 years), 19 +/- 4 months after implantation of different sizes (25 to 31 mm) of a given type of bioprosthesis. Areas obtained with both the continuity equation, using stroke volume measured in the left ventricular outflow tract, and the pressure half-time method are compared to known prosthetic areas derived from an in vitro hydraulic model. Areas calculated by the continuity equation correlate well with in vitro areas (r = 0.82, standard error of the y estimate = 0.1 cm2, p less than 0.001), and are within the range of predicted in vitro values in 92% of cases. Areas derived by the pressure half-time method do not correlate with in vitro areas (r = 0.15, p greater than 0.3) or continuity equation areas (r = 0.23, p greater than 0.2), and are above the range of predicted values in 69% of cases. Correlations are also found between continuity equation areas and the peak and mean valvular gradients (r = 0.59, p less than 0.005 and r = -0.63, p less than 0.0005, respectively). Taking the effect of cardiac output on gradients into account results in projected relations between indexed prosthetic areas and the pressure gradients at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Contribution to the theoretical study of the Doppler half-time method for the measurement of the cross-sectional area of the mitral valve.

The acceleration term is included in the expression of the Bernoulli equation and an application of this formalism to the study of the Doppler measured mitral flow velocity is discussed. Based on calculation of the time-to-time variation of the parameters involved, a possible theoretical explanation of the pressure half-time method for the measurement of the cross-sectional area of the mitral valve is given.

Binomial Distribution↗

PubMed1990

Validation and applications of indexed aortic prosthetic valve areas calculated by Doppler echocardiography.

Doppler echocardiographic evaluation of aortic valve prostheses is based on the use of variables heretofore validated mostly for native valves. Accordingly, this study examined the validity and relative usefulness of the Doppler valve gradient and area measurements in 31 patients (mean age 69 +/- 10 years) 20 +/- 4 months after implantation of a given type of aortic bioprosthesis ranging in size from 19 to 29 mm. Valve area data obtained with both the standard and simplified continuity equations were compared with known in vitro prosthetic valve area measurements and an excellent correlation was obtained between the standard and simplified continuity equations (r = 0.98, SEE +/- 0.07 cm2, p less than 0.0005) and between in vivo and known in vitro prosthetic valve areas (r = 0.86, SEE +/- 0.16 cm2, p less than 0.0005). Peak gradient ranged from 10.8 to 75.0 mm Hg (mean 35 +/- 16) and mean gradient from 7.6 to 43.7 mm Hg (mean 20.5 +/- 9.5). The correlations between prosthetic valve gradient and in vivo area were r = -0.53, SEE +/- 14 mm Hg and r = -0.49, SEE +/- 8.63 mm Hg for peak and mean gradient, respectively. These relations were improved by indexing valve area by body surface area. The best correlations were obtained between indexed valve area and a quadratic function of the gradient (r = -0.72, SEE +/- 11.72 mm Hg and r = -0.70, SEE +/- 7.28 mm Hg for peak and mean gradient, respectively), reflecting a curvilinear relation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

Beneficial long-term effects of hydralazine in aortic regurgitation.

The long-term effects of vasodilators in asymptomatic patients with aortic regurgitation have not been studied extensively. We retrospectively reviewed the echocardiograms of 19 asymptomatic patients with significant aortic regurgitation followed up annually for up to 4 years (average +/- SD, 3.1 +/- 0.7 years). Of these 19 patients, 12 were not receiving vasodilators and 7 were receiving hydralazine hydrochloride, 40 to 200 mg daily. In the patients not receiving vasodilators, left ventricular diastolic and systolic dimensions increased progressively in all patients by an average of 8% and 13%, respectively, after 3 years. In the patients receiving hydralazine, left ventricular dimensions increased by 9% and 5% in the year or more before hydralazine use and decreased by 7% and 7%, respectively, during the first year after using hydralazine. The reduction was observed in all patients during the first year, but an increase was detected in 3 patients followed up beyond that period. The results suggest that the progression of left ventricular dilatation in asymptomatic patients with aortic regurgitation can be delayed by long-term therapy with vasodilators. Pending further confirmation, such therapy may possibly influence the natural history of the disease and delay the timing of operation.

Adult↗

PubMed1989

Some applications of the P-V relation to the study of left ventricular performance.

There is still controversy as to which characteristics of the pressure-volume relation should be used to define myocardial contractility. In the present study a mathematical model for the left ventricle as a two-dimensional cylinder contracting radially and symmetrically was used to establish a relation between a calculated intramyocardial pressure (Dh) and the P-V relation (PVR) at end-systole. Four new indices are introduced that allow a better assessment of change in inotropic state of the myocardium, namely the calculated intramyocardial pressure (Dh), the calculated resultant pressure across the inner surface of the myocardium (Dh-P) (P = cavity pressure), the work Wt related to the pressure (Dh) and the work Wd related to the pressure (Dh-P). A relation between Wt and Wd and different parts of the area under the PVR is established. Indices derived in this manner from the PVR to study changes in myocardial contractility appear to have a clear physical meaning.

Heart↗

PubMed1989

In situ right ventricular thrombus secondary to heparin induced thrombocytopenia.

Heparin induced thrombocytopenia (HIT) is a relatively common complication of heparin therapy, occurring in approximately 5% of patients treated with this drug. HIT may be associated with diffuse arterial and venous thrombosis. The case of a patient without underlying heart disease who developed a right ventricular thrombus and recurrent pulmonary emboli in association with and possibly as a complication of HIT is reported. Ancrod was used as an alternative to heparin for the time required to obtain an effective oral anticoagulant effect. The patient recovered completely and has no residual right ventricular thrombus.

Adult↗

PubMed1988

Survival with painless strongly positive exercise electrocardiogram.

To determine the prognosis of patients with painless strongly positive exercise electrocardiogram, the 6-year cumulative survival rate was computed for 298 medically treated patients who terminated their exercise test with or without angina. All had horizontal or downsloping ST depression greater than or equal to 2 mm during a treadmill exercise test according to the standardized multistage Bruce protocol. Of the 298 patients, 119 terminated the exercise test because of dyspnea or fatigue and 179 stopped because of angina. Among the 119 patients without angina, there were 18 deaths, 16 from coronary artery disease (CAD), of which 8 occurred suddenly. Among the 179 patients with exercise-induced angina, 36 died, 33 from CAD, of which 13 were sudden deaths. The overall 6-year survival rate was 85 +/- 3% for patients without angina and 80 +/- 3% in those with angina (p less than 0.05). However, patients without angina achieved a significantly longer duration of exercise and had higher maximal heart rate and systolic blood pressure during exercise. In both groups, survival decreased with decreasing duration of exercise. In patients without angina, the 6-year survival rate was 97 +/- 3% in those achieving stage IV (greater than or equal to 541 s), 87 +/- 4% in stage III (361 to 540 s), 64 +/- 13% in stage II (181 to 360 s) and 60 +/- 15% in stage I (less than or equal to 180 s).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1988

A new and simple method to measure maximal aortic valve pressure gradients by Doppler echocardiography.

Most echocardiographic laboratories now use continuous-wave Doppler to measure transvalvular pressure gradients in patients with valvular aortic stenosis (AS). In many cases, particularly in the elderly, this technique can be difficult and time-consuming, and there is no immediate means of verifying the accuracy of the results. In the present study, a new and simple method is proposed to calculate maximal aortic valve gradients from the pulsed-wave Doppler tracing recorded in the left ventricular outflow tract. The method consists of calculating maximal aortic flow velocity and thus the maximal gradient by extrapolating to their point of intersection the initial accelerating velocity and the terminal decelerating velocity recorded on the pulsed Doppler tracing. In 20 patients with varying degrees of AS, there was an excellent correlation (r = 0.96, p less than 0.001) between the results obtained by this method and those obtained by continuous-wave Doppler. In 10 patients who had cardiac catheterization, the results also correlated well with the maximal gradient (r = 0.93, p less than 0.001) measured at cardiac catheterization. Because the method is simple, it should become an integral part of the Doppler examination in patients with AS. Its main advantages will be to serve as an independent confirmation of the results obtained by continuous-wave Doppler and to reduce in many patients the duration of the examination.

Adult↗

PubMed1988

Endurance vs. strength training: comparison of cardiac structures using normal predicted values.

There are still disagreements concerning the adaptation of cardiac structures in relation to different training stimuli. To eliminate some of the variance due to individual differences in body surface area, we utilized a new approach based on the calculation of the percentages of each individual's normal predicted values (%NPV). We studied 46 strength (S, bodybuilders) and 57 endurance (E, runners) athletes. Left ventricular (LV) mass was 143.8 +/- 21.9 %NPV (mean +/- SD) in E vs. 134.3 +/- 23.4 %NPV in S (P less than 0.05), and LV volume was 131.0 +/- 24.0 %NPV in E vs. 120.0 +/- 25.5 %NPV in S (P less than 0.05). Moreover, the LV wall thickness-to-radius ratio did not differ from normal values in either group. From these data we conclude that 1) cardiac modifications are greater in E than S, 2) the predominant stimulus is a volume overload type in both groups, and 3) concentric LV hypertrophy may not be as prevalent in S as previously suggested.

Adult↗

PubMed1988

[Cardiac output and left ventricular function].

The Doppler ultrasound cardiography theoretically enables to measure the output at different sites of the cardiovascular system. Several studies now demonstrate a good correlation with haemodynamics. Doppler output measurements are however very sensitive to errors, even small ones; the examination must therefore by very thoroughly carried out in order to be valid. The velocity and acceleration of the blood flow may also be measured by Doppler, but the clinical applications for evaluation of the systolic function of the left ventricle still remain limited. The field which now appears to be the most promising is that of analysis of the diastolic function of the left ventricle, based on the mitral diastolic flow, especially in patients presenting a left heart failure with a normal systolic function as well as in certain conditions of volume overload. The non invasive evaluation of the intracardiac pressures with the Doppler, also proves interesting in some cases.

Blood Pressure↗

PubMed1988

A new porcine bioprosthesis: design rationale and early clinical experience.

The Medtronic Intact valve is a third-generation porcine bioprosthesis produced using a leaflet fixation process which imposes virtually zero hydrostatic pressure. This fixation method provides optimal preservation of the original leaflet structure and integrity and should result in an improvement in durability compared to conventional preservation techniques. The biomechanical basis for this hypothesis is presented along with early experience with 118 patients (125 valves). There have been no complications related to primary valve failure and the incidence of other valve related events is acceptable.

Aortic Valve↗