Left Ventricular-aortic Pressure Gradient Research Articles

Comparison of the Clinical Outcomes and Hemodynamic Performance between the 19-Mm Mosaic and 19-Mm TrifectaTM Bioprosthesis

Background: We evaluated and compared short- (≤ 3 months) and mid-term (≥ 4 months) clinical outcomes and hemodynamic performances of the 19-mm Mosaic® and 19-mm TrifectaTM bioprostheses for aortic valve replacement. Methods: 193 patients underwent aortic valve replacement: 37 received the 19-mm Mosaic® prosthesis (Group M) and 12 received the 19-mm TrifectaTM prosthesis (Group T). Pre- and postoperative echocardiographic parameters and New York Heart Association classes were evaluated in both groups. Results: Baseline characteristics and preoperative echocardiographic parameters were similar between the groups. The New York Heart Association class improved in both groups. The mean left ventricular-aortic pressure gradient was 22.6 mmHg ± 8.4 mmHg in Group M and 15.0 mmHg ± 6.2 mmHg in Group T. The left ventricular mass index was 99.6 ± 27.6 g/m2 and 99.0 ± 20.0 g/m2 respectively, with significant improvements in both groups. Left ventricular mass index regression during the mid-term period showed no significant difference between the groups, despite a higher-pressure gradient and smaller effective orifice area index in the Mosaic® group. Patient-prosthesis mismatch occurred in 20 patients in the Mosaic® group, with no significant differences in the postoperative left ventricular mass indices and New York Heart Association classes between the patientprosthesis mismatch and no patient-prosthesis mismatch subgroups in the Mosaic® group. Conclusion: Compared with the 19-mm TrifectaTM bioprosthesis, the 19-mm Mosaic® bioprosthesis showed similar satisfactory improvement in the New York Heart Association class grade and reduction in the left ventricular mass index, despite a higher-pressure gradient and smaller effective orifice area index.

Transcatheter Aortic Valve Implantation and Morbidity and Mortality-Related Factors: a 5-Year Experience in Brazil.

BackgroundTranscatheter aortic valve implantation has become an option for high-surgical-risk patients with aortic valve disease.ObjectiveTo evaluate the in-hospital and one-year follow-up outcomes of transcatheter aortic valve implantation.MethodsProspective cohort study of transcatheter aortic valve implantation cases from July 2009 to February 2015. Analysis of clinical and procedural variables, correlating them with in-hospital and one-year mortality.ResultsA total of 136 patients with a mean age of 83 years (80-87) underwent heart valve implantation; of these, 49% were women, 131 (96.3%) had aortic stenosis, one (0.7%) had aortic regurgitation and four (2.9%) had prosthetic valve dysfunction. NYHA functional class was III or IV in 129 cases (94.8%). The baseline orifice area was 0.67 ± 0.17 cm2 and the mean left ventricular-aortic pressure gradient was 47.3±18.2 mmHg, with an STS score of 9.3% (4.8%-22.3%). The prostheses implanted were self-expanding in 97% of cases. Perioperative mortality was 1.5%; 30-day mortality, 5.9%; in-hospital mortality, 8.1%; and one-year mortality, 15.5%. Blood transfusion (relative risk of 54; p = 0.0003) and pulmonary arterial hypertension (relative risk of 5.3; p = 0.036) were predictive of in-hospital mortality. Peak C-reactive protein (relative risk of 1.8; p = 0.013) and blood transfusion (relative risk of 8.3; p = 0.0009) were predictive of 1-year mortality. At 30 days, 97% of patients were in NYHA functional class I/II; at one year, this figure reached 96%.ConclusionTranscatheter aortic valve implantation was performed with a high success rate and low mortality. Blood transfusion was associated with higher in-hospital and one-year mortality. Peak C-reactive protein was associated with one-year mortality.

Mid-Term Outcomes After Aortic Valve Replacement With the 17-mm St. Jude Medical Regent Valve

When aortic valve replacement (AVR) is performed in patients with a small aortic annulus, prosthesis-patient mismatch (PPM) is of concern. We investigated the mid-term outcomes of AVR with a 17-mm mechanical prosthesis. Seventy-eight patients with aortic stenosis underwent AVR with a 17-mm St. Jude Medical Regent prosthesis. Echocardiography was performed preoperatively, at discharge, and at follow-up (mean follow-up, 33 months). Patients were divided into 2 groups: with and without PPM at discharge. Between-group differences in postoperative variables, particularly survival, were analyzed. Overall hospital mortality was 2.6%. Actuarial 1- and 5-year survival rates were 95% and 79%, respectively. Diabetes and renal insufficiency were associated with long-term mortality. Freedom from major adverse valve-related cardiac events at 1 year and 5 years was 97.3% and 93.9%, respectively. Diabetes was shown to be an independent risk factor for major adverse valve-related cardiac events. Echocardiography 13 months after AVR showed a significant increase in mean effective orifice area index, decrease in mean left ventricular-aortic pressure gradient, and decrease in mean left ventricular mass index. PPM at discharge did not influence long-term survival or left ventricular mass regression. The 17-mm Regent prosthesis provided satisfactory clinical and hemodynamic results. It is a reliable choice for patients with a small aortic annulus.

A Surgical Case of Prosthetic Valve Endocarditis with a Difficult Diagnosis

Early diagnosis and treatment of prosthetic valve endocarditis (PVE) is important because it has a high mortality rate. We report a case of PVE which was difficult to diagnose. A 36-year-old man, who had undergone an aortic valve replacement (AVR) 7 years prior, was hospitalized with a high fever of unknown origin. We could not detect a stuck valve, vegetations or abscesses using echocardiography, and the peak aortic transvalvular pressure gradient had increased to 81 mmHg. We suspected PVE and initiated intravenous antibiotic therapy immediately. On day 5, echocardiography demonstrated an abnormal shadow directly under the prosthesis, and we definitively diagnosed PVE and performed an operation. Intraoperatively, the prosthesis was not vegetative, but the left ventricular outflow tract was filled with vegetation that was nearly obstructing it. After dissecting the infectious focus, we performed a re-AVR. Postoperative echocardiography showed that the peak left ventricular aortic pressure gradient decreased to 30 mmHg. Obstructive vegetation is difficult to diagnose by preoperative echocardiography.

Hemodynamics and Outcomes of Aortic Valve Replacement with a 17- or 19-mm Valve

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern because it may affect postoperative clinical status. We conducted a retrospective study of outcomes in 65 patients with aortic stenosis requiring valve replacement. Fifty were given a 17-mm or 19-mm St. Jude Regent mechanical valve, and 15 were given a 19-mm Medtronic Mosaic bioprosthesis. Echocardiography was carried out preoperatively, at discharge, and at follow-up. There was 1 (2%) operative death in the Regent group and none in the Mosaic group. There was no valve-related event. Follow-up echocardiography in both groups revealed a significant increase in the mean effective orifice area index, a decrease in the mean left ventricular-aortic pressure gradient, and a decrease in the mean left ventricular mass index. Prosthesis-patient mismatch (effective orifice area index <0.85 cm(2) · m(-2)) existed in 13 (26%) patients in the Regent group and 11 (73%) in the Mosaic group at discharge. All patients improved to New York Heart Association functional class II or better. A small-sized prosthesis may provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus.

The 17-mm St. Jude Medical Regent Valve Is a Valid Option for Patients With a Small Aortic Annulus

When aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern. Such prosthesis-patient mismatch may affect postoperative clinical status and survival. We investigated the outcomes of isolated aortic valve replacement performed with a 17-mm mechanical prosthesis in patients with aortic stenosis. Twenty-three patients with aortic stenosis (mean age, 74.6 +/- 6.3 years) underwent isolated aortic valve replacement with a 17-mm St. Jude Medical Regent prosthesis. Mean body surface area was 1.41 +/- 0.13 m(2). Preoperative echocardiography yielded a mean aortic valve area of 0.36 +/- 0.10 cm(2)/m(2), a mean left ventricular-aortic pressure gradient of 68.4 +/- 25.3 mm Hg, and a mean left ventricular mass index of 200 +/- 69 g/m(2). There was no operative mortality, and there were no valve-related events. Echocardiography at 14.0 +/- 10.0 months after aortic valve replacement showed a significant increase in the mean effective orifice area index (0.95 +/- 0.24 cm(2)/m(2)), decrease in the mean left ventricular-aortic pressure gradient (17.4 +/- 8.2 mm Hg), and decrease in the mean left ventricular mass index (124 +/- 37 cm(2)/m(2)). Prosthesis-patient mismatch (effective orifice area index < 0.85 cm(2)/m(2)) was present in 8 patients at discharge. In these patients as well as in those without prosthesis-patient mismatch, the left ventricular mass index decreased remarkably during follow-up. Aortic valve replacement with a 17-mm Regent prosthesis appears to provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus. Remarkable left ventricular mass regression during follow-up was achieved irrespective of the effective orifice area index at discharge.

An Experimental Study of Apico-Aortic Valved Conduit (AAVC) for Surgical Treatment of Aortic Stenosis in Dogs

A new valved conduit was developed using a canine aortic valve. The bioprosthetic valve was fixed with glutaraldehyde and epoxy compound (Denacol-EX313/810). A vascular graft composed of ultra-fine polyester fiber (10 mm in diameter, 200 mm in length) was used. Four dogs underwent apico-aortic valved conduit (AAVC) implantation and aortic banding (bypass group, BG), while another 4 dogs underwent aortic banding without AAVC implantation (control group, CG). Cardiac catheterization and angiocardiography were performed for assessment of hemodynamics 2 weeks and 6 months after surgery. Left ventricular systolic pressure, left ventricular end-diastolic pressure and the left ventricular-aortic pressure gradient differed significantly (P<0.01) between the BG and CG dogs. Left ventricular angiocardiography showed patency of the valved conduit in all the BG dogs. Echocardiography was performed before and 2, 4 and 6 months after surgery, and showed that while pressure overload caused concentric myocardial hypertrophy in the CG dogs, the left ventricle dilated eccentrically in the BG dogs. Furthermore, relief of left ventricular pressure overload by AAVC was maintained.

Haemodynamic Evaluation of Retrograde versus Anterograde Delivery of Cardioplegic Solution in Aortic Valve Replacement

A total of 44 patients undergoing isolated aortic valve replacement received either anterograde (20 patients) or retrograde (24 patients), cold St Thomas's Hospital cardioplegia. The patients were similar with respect to age, sex, left ventricular ejection fraction, left ventricular-aortic pressure gradient, cross-clamping time and mean dose of cardioplegia. After surgery, there were no differences in enzyme release, low cardiac output syndrome, rhythm disturbances or clinical outcome between the two groups. Analysis of the postoperative haemodynamic data, however, suggests better preservation of left ventricular contractility with retrograde delivery of cardioplegic solution.

Intraventricular repair for Taussig-Bing anomaly

Among 41 patients with Taussig-Bing anomaly who underwent intracardiac repair, 10 patients were treated by intraventricular rerouting repair. The ages at operation ranged form 1 month to 8 years (average 2 years 3 months). Primary repair was done in four (average age 2 years 7 months), and repair was done after pulmonary artery banding in six patients (average age 2 years 2 months). The relationship of the great arteries was side by side in nine patients and oblique in one. After extensive resection of the infundibular septum, a distance of 8 to 18 mm from the tricuspid ring or chordae to the pulmonary valve was obtained (24% to 71% of total circumference for the subaortic route). The subaortic route was created to obtain an internal diameter at least equal to that of the aortic route. Tricuspid chordal or papillary muscle reattachment was performed in two patients. There were no early or late deaths. Follow-up ranged from 1 year 4 months to 22 years 3 months (average 5 years 8 months), and reoperation was required in one patient for residual pulmonary stenosis. The intraoperative pressure gradient between the left ventricle and aorta was 0 to 24 mm Hg (average 10.3 mm Hg), and postoperative study showed the gradients to be less than 19 mm Hg (n = 8). The age at operation, left ventricular-aortic pressure gradient, and postoperative tricuspid regurgitation were not significantly affected by the presence of severe hypertrophy of the infundibular septum (n = 4). These results indicate that intraventricular rerouting may be feasible in most patients who have the Taussig-Bing anomaly with side-by-side or similar relationships of the great arteries, and the age and conal anatomic variations do not appear to be significant limiting factors.

Hemodynamic determinants of the peak systolic left ventricular-aortic pressure gradient in children with valvar aortic stenosis

The peak systolic pressure gradient (the difference between peak left ventricular [LV] and peak aortic systolic pressures) has been used for many years as a primary measure of severity in children with valvar aortic stenosis (AS). 1–3 Reliance on the peak systolic pressure gradient in clinical decision-making was based on the practice of measuring the gradient at catheterization by withdrawing a single catheter from the left ventricle to aorta. In recent years it has become common, however, to measure LV and aortic pressures simultaneously with dual catheter techniques. 4 The time-honored peak systolic gradient does not actually exist in time, because peak LV pressure in AS occurs well before peak aortic systolic pressure. The pressure gradients that actually exist in real time between the left ventricle and aorta (the instantaneous gradients) vary throughout systole. These instantaneous pressure gradients, which include peak instantaneous gradient and mean systolic gradient (the integral of the systolic instantaneous gradients) can be estimated noninvasively, 5–7 unlike peak systolic gradient. Nevertheless, clinicians continue to rely on peak systolic pressure gradient as an important index of severity for clinical decision-making in children with valvar AS. The purpose of this study was to define, at cardiac catheterization, the relation between peak, mean and peak instantaneous systolic pressure gradients in children with valvar AS.

“Acquired” discrete subvalvular aortic stenosis: Natural history and hemodynamics

Discrete subvalvular aortic stenosis is a progressive lesion. Most reported cases have had a measurable left ventricular. aortic gradient that progressed in severity. This report describes 35 patients in whom no significant left ventricular-aortic obstruction was noted at initial cardiac catheterization, but who later were shown to have significant subvalvular aortic stenosis. In 24 of the 35 cases, absence of a significant left ventricular-aortic gradient (≤10 mm Hg) was documented at initial cardiac catheterization. In 11 patients, a left ventricular-aortic pressure gradient was not obtained or not sought in the absence of clinical evidence of an obstructive lesion. In each case, discrete subaortic stenosis was not noted on angiography.Associated lesions included ventricular septal defect in 7, patent ductus arteriosus in 12, coarctation of the aorta in 8, pulmonary stenosis in 3, atrioventricular canal in 2 and miscellaneous lesions in 3 cases. The 35 patients had documentation of subvalvular aortic stenosis 3 months to 19 years after their initial study based on repeat catheterizations in 26, echocardiography in 6 or discovery at surgery in 3 cases. There were eight children with coarctation and no left ventricular-aortic gradient who developed significant subvalvular stenosis at a median of 2 years 9 months after initial cardiac catheterization. Of 30 patients with associated lesions, 23 had surgical intervention before development of subvalvular aortic stenosis, but only 5 of 17 patients with ventricular septal defect had surgical repair or palliation specifically for the interventricular communication before development of subvalvular aortic stenosis. Thirty patients required surgery for subvalvular obstruction at a median of 7.7 years after initial catheterization.It is concluded that discrete subvalvular aortic stenosis may develop despite prior documentation of no left ventricular-aortic gradient. Although subvalvular aortic stenosis may have a preexisting substrate, the lesion can present as an “acquired” disease with progressive hemodynamic severity.

The perioperative fate of residual gradients after repair of discrete subaortic stenosis and time-related blood levels of catecholamines

The fate of the residual peak systolic left ventricular-aortic gradient was studied perioperatively in 14 patients with membranous discrete subaortic stenosis. In nine (group A) the initial postrepair left ventricular-aortic gradient was greater than 35 mm Hg (mean 56.8 +/- 13.4), and in five (group B) there was no significant postoperative gradient (mean 15.3 +/- 3.2 mm Hg). The operation included membranectomy and myectomy. Peak left ventricular-aortic pressure gradient, endogenous levels of norepinephrine, peak rate of rise of left ventricular pressure, cardiac index, systemic vascular resistance, heart rate, and central venous pressure were recorded at the end of cardiopulmonary bypass and in 3-hour intervals for the next 9 hours. In group A during that period there was a 67% reduction in peak systolic left ventricular-aortic gradient (from 56.8 +/- 13.4 to 18 +/- 14 mm Hg, p less than 0.001). Concomitant reduction in the initial endogenous norepinephrine level was observed (from 982.1 +/- 181 to 422.6 +/- 109 pg/ml, p less than 0.001). A consistent linear relationship between norepinephrine levels and peak systolic left ventricular-aortic gradient was found (r = 0.78). Systolic left ventricular pressure decreased from 174.2 +/- 24.8 to 113.8 +/- 14.7 mm Hg (p less than 0.001). Marked reduction in peak rate of rise of left ventricular pressure (from 3455 +/- 636 to 2161 +/- 680 mm Hg/sec, p less than 0.001) was observed. Cardiac index increased and systemic vascular resistance decreased during the study period (from 2.11 +/- 0.2 to 3.07 +/- 0.26 L/min, p less than 0.001, and from 2172 +/- 331 to 1233 +/- 202 dynes/sec/cm-5, p less than 0.001, respectively). There were no significant changes in heart rate (p = not significant) and central venous pressure p = not significant). Some of the residual perioperative left ventricular-aortic gradients in patients with discrete subaortic stenosis undergoing repairs are dynamic and transient, and are probably related to increased postoperative sympathetic activity.

Influence of aortic stenosis on the hemodynamic importance of coronary artery narrowing in dogs without left ventricular hypertrophy

Coronary hemodynamic effects of controlled left ventricular outflow obstruction stimulating aortic valve stenosis were studied in 20 open-chest dogs, with and without graded coronary artery diameter narrowing. Aortic stenosis was regulated so that a mean left ventricular-aortic pressure gradient of 46 +/- 20 mm Hg (mean +/- standard deviation) was created as both heart rate and stroke volume were unchanged. In addition, during aortic stenosis, mean aortic pressure (105 +/- 17 to 84 +/- 15 mm Hg, p less than 0.05) and diastolic pressure time index/systolic pressure time index ratio (1.2 +/- 0.3 to 0.6 +/- 0.2, p less than 0.05) decreased and end-diastolic left ventricular pressure (7 +/- 4 to 14 +/- 6 mm Hg, p less than 0.05) increased. With no coronary narrowing, mean coronary flow increased during aortic stenosis (53 +/- 23 to 62 +/- 23 ml/min) as the percentage of diastolic flow increased (83 +/- 6 to 89 +/- 4) and endocardial/epicardial ratio decreased (1.14 +/- 0.16 to 0.95 +/- 0.24) (all p less than 0.05). Peak reactive hyperemic flow also decreased (168 +/- 85 to 125 +/- 73 ml/min, p less than 0.05). This value with no coronary narrowing was similar to peak hyperemic flow with 60% narrowing without aortic stenosis. With 90% coronary narrowing, mean coronary flow decreased with or without aortic stenosis. Transmural flow distribution also decreased but was lower during aortic stenosis (0.86 +/- 0.19 to 0.61 +/- 0.25, respectively; p less than 0.05). These data suggest that although mean coronary flow is increased during aortic stenosis, endocardial flow may be limited, and coronary reserve exposed during reactive hyperemia appears decreased. When a coronary artery is narrowed, aortic stenosis has an even more important hemodynamic influence on the coronary circulation.

Postextrasystolic changes in systolic time intervals in the assessment of hypertrophic cardiomyopathy.

To determine if postextrasystolic changes in systolic time intervals can be used to estimate the severity of resting or provocable left ventricular outflow pressure gradient, we studied the cardiac catheterisation records of 42 patients with hypertrophic cardiomyopathy looking for instances of a single premature beat preceded by a control sinus beat and followed by a postpremature sinus beat. There were 75 such instances in 25 patients. In comparison to the control beat, the pre-ejection period in the postpremature beat was shorter by deltaPEP = -20 +/- 11 ms in 73 of 75 instances, and remained unchanged in two. The ejection time in the postpremature beat was invariably longer by deltaET = 37 +/- 20 ms (range: 10 to 85 ms) and the pre-ejection period/ejection time ratio lower than control by delta(PEP/ET) = -0 . 10 +/- 0 . 05 (range: -0 . 01 to -0 . 25). Total electromechanical systole in the postpremature beat was shorter (11/75), the same (10/75), or longer (53/75) than in the control beat, the overall change being deltaEMS = -18 +/- 22 ms. Both deltaPEP and delta(PEP/ET) correlated poorly with the systolic peak left ventricular-aortic pressure gradient in either the control beat (Gc) or the postpremature beat (Gx), and also with the change in gradient (delta G) from the control to the postpremature beat. In contrast, significant linear correlations were found between delta EMS and either Gc, Gx, or delta G; and also between deltaET and either Gc, Gx, or deltaG. Since internal and external measurements of ejection time are known to be almost identical, the regression equation (deltaG = 1 . 65 delgaET -9) relating deltaET and deltaG should be useful for the non-invasive assessment of the magnitude of provocable left ventricular outflow pressure gradient in patients with hypertrophic cardiomyopathy with spontaneous or externally-induced premature beats.

Rest and exercise hemodynamics in children before and after aortic valvotomy

The rest and exercise hemodynamics in children with congenital valvar aortic stenosis were studied before and after aortic valvotomy. Eighteen patients were studied at rest; ten of the 18 patients were also studied during supine leg exercise using a bicycle ergometer. Aortic valvotomy resulted in a significant reduction in the mean left ventricular-aortic pressure gradient and in peak left ventricular systolic pressure with an increase in aortic valve area in most patients. There was an associated increase in the subendocardial blood flow assessed indirectly by the DPTI × O 2 c SPTI ratio. There was a minor increase in the degree of aortic insufficiency in most patients. Although, in general, there was significant hemodynamic improvement, three of the 18 patients still had significant residual stenosis after surgery and another four patients had a major increase in aortic insufficiency. The three patients with residual obstruction and one of the four patients with moderate to severe aortic insufficiency still had a DPTI × O 2 c SPTI ratio of less than 10, suggesting possible residual subendocardial ischemia. Also, the increased left ventricular end-diastolic pressures (LVEDP) present in nearly 50% of the patients before surgery did not change significantly after surgery. Three patients showed an actual increase in LVEDP after surgery. Before surgery, the left ventricular systolic pressure and mean gradient increased on exercise, but this increase was proportionately less than the increase in cardiac output, so that calculated aortic valve area increased on exercise. The DPTI × O 2 c SPTI ratio decreased significantly on exercise, suggesting an increase in myocardial ischemia. Successful surgery resulted in a reduction in left ventricular systolic pressure and mean left ventricular-aortic gradient on exercise, and in improvement in the subendocardial blood flow as assessed by the DPTI × O 2 c SPTI ratio. In general, children with severe aortic stenosis have relatively normal cardiac function on exercise. Some children did show a reduction of stroke index on exercise in spite of rising LVEDP. However, stroke work index increased in all of our children. Adult studies have shown many patients with decrease in stroke work index relative to LVEDP on exercise. The results of pre- and postoperative rest and exercise hemodynamics may be useful in evaluating results of surgery; the postoperative hemodynamic evaluation including the use of DPTI × O 2 c SPTI ratio provides additional useful information which can be used in making decisions concerning exercise activity after surgery.

Progression of Aortic Stenosis

We assessed progressive stenosis of the aortic valve in 11 adult patients (mean age of 48 years) with aortic stenosis who had undergone two cardiac catheterizations without intervening aortic valve surgery. The mean time between cardiac catheterization was 59 months (range 20 to 133). No patients had mitral valve disease. Two patients had coronary artery disease. The results showed that progressive stenosis of the aortic valve occurred in 10 of 11 patients with a significant decrease in the calculated mean aortic valve area from 1.2 +/- 0.2 sq cm to 0.7 +/- 0.1 sq cm (P less than 0.005); a significant increase in mean left ventricular peak systolic pressure from 149 +/- 8 mm Hg to 199 +/- 3 mm Hg (P less than 0.01), and a significant increase in mean left ventricular aortic pressure gradient from 31 +/- 4 mm Hg to 75 +/- 13 mm Hg (P less than 0.005). On an individual basis, the change in left ventricular pressure and the left ventricular-aortic gradient did not always reflect the decrease in aortic valve area because of variations in cardiac output. The shortest period of time in which progression of aortic stenosis occurred was 27 to 29 months. Thus, progressive stenosis of the aortic valve occurs in adults with isolated aortic valvular stenosis. Significant decrease in the aortic valve area can develop in as short a period as 27 to 29 months.