High Transprosthetic Gradients Research Articles

194 THROMBOEMBOLIC ACUTE ST ELEVATION MYOCARDIAL INFARCTION AFTER TRANSCATHETER VALVE IMPLANTATION

Abstract Transcatheter aortic valve implantation (TAVI) is an established treatment of severe symptomatic aortic valve stenosis and is an effective and less invasive treatment option compared with conventional surgical aortic valve replacement (SAVR) for patients considered inoperable or at high surgical risk. Thromboembolic and bleeding complications negatively impact recovery and survival after TAVI. This case describes one of the few reported TAVI-associated myocardial infarction due to thrombosis of the prosthetic aortic valve. A 82-years-old woman, suffering from severe symptomatic aortic stenosis, underwent TAVI. Before the procedure, coronary artery disease was excluded by invasive coronary angiography. Since the time of the discharge the patient didn't assume any therapy with aspirin or other antithrombotic drugs. A month after TAVI she complained persistent epigastric pain and was admitted to our department for anterior ST elevation myocardial infarction. Coronary angiography highlighted a monovascular coronary artery disease with thrombotic occlusion of the first diagonal and of the distal left anterior descending coronary artery. In consideration of the thrombotic load thyrofiban was started and it was performed a chest contrast CT which confirmed the diagnostic suspicion of bioprosthetic valve thrombosis. She was first treated with unfractionated heparin (UFH) and then oral anticoagulant therapy with warfarin was started. Echocardiograms (echo) showed a severely reduced systolic function (EF 25%) and high trans-prosthetic gradients (mean transprosthetic pressure gradient of 30 mmHg). On the 8th day after hospitalization she complained chest pain with evidence of moderate pericardial effusion. Epistenocardica pericarditis was therefore diagnosed and the patient started acetylsalicylic acid therapy with progressive clinical, instrumental and laboratory improvement. After 10 days of anticoagulation therapy, she underwent a transesophageal echocardiogram which turned out negative for bioprosthetic valve thrombosis. The predischarge transthoracic echocardiography showed severely reduced systolic function (EF 30%) with a mean transprothesic gradient of 12 mmHg; the circumferential pericardial effusion was mild-moderate but not haemodynamically significative. Therapy at discharged included warfarin and aspirin. Ten days after an echo showed a reduction of the pericardial effusion, an improved systolic function (EF 42%) and mean transprothesic gradient not changed significantly since discharge. Prosthetic valve thrombosis has been reported in up to 40% of patients after TAVI and this case hightlights the importance of antithrombotic therapy after this procedure. Therapeutic anticoagulation appears to be the only non-invasive treatment for resolving valve thrombosis but it is not clear how long this therapy should last for the prevention of prosthetic valve thrombosis.

C33 PERCUTANEOUS CLOSURE OF MITRAL PARAVALVULAR LEAK (PVL): WHEN REVERSAL MAKES ALL THE DIFFERENCE

Abstract PVL is a complication associated with the implantation of a prosthetic valve. Since surgical re–intervention has a high operative risk, percutaneous closure (PC) has emerged due to its reduced invasiveness and the development of dedicated materials. We describe the case of a 66–year–old man with a mechanical oscillating disc mitral prosthesis who was admitted for acute heart failure. An echo showed a left ventricle with normal motion and a postero–medial mitral PVL with significant regurgitation. A transoesophageal echo confirmed the PVL in the 5 o’clock viewing portal with severe regurgitation. After optimising the medical therapy and with no change in echo findings, a cardiac catheterisation showed persistent post–capillary pulmonary hypertension, and therefore PC of the PVL was scheduled. Given the postero–medial location of the PVL, a transseptal puncture was performed using a 8.5 Fr Agilis introducer (Terumo) with telescoping system of a 6 r. JR4 catheter. The PVL was passed through with a Terumo 0.035 J–shaped guide, but without managing to advance the catheter beyond the leak. The guide was therefore advanced into the abdominal aorta and an arteriovenous circuit was created, which allowed the catheter to be advanced beyond the PVL and a closure device (AVPIII 14/5,Abbott St.Jude) was positioned with anterograde placement, with a distal disc on the ventricular side. Obliteration of the PVL, interference with the prosthetic disc and high transprosthetic gradients were observed despite several attempts to relocate the AVP, which was therefore removed. A second procedure was performed at a distance, creating a similar arteriovenous circuit by using a long introducer (110cm–Cook) which was advanced from the femoral artery beyond the leak in the opposite direction. An AVPIII (12/5) with a distal disc on the atrial side was positioned, this time with retrograde placement, with effective closure of the PVL and minimal residual regurgitation, without interference with the prosthesis. The course was free of complications; after one month the echo confirmed the result. Transcatheter closure of the PVL is a complex procedure, but relatively safe in experienced hands. This case is of particular interest due to the difficulty presented by the location of the PVL, which required measures of high technical complexity and because it describes a possible complication of the procedure, which was resolved by the simple reversal of the placement of the device.

Significant intra-valvular pressure loss across EPIC SUPRA and perimount magna supra-annular designed aortic bioprostheses in patients with normal aortic size

Doppler-derived trans-prosthetic gradients are higher and the estimated effective valve area is smaller than the catheter-derived and directly measured hemodynamic values, mostly due to pressure recovery phenomenon. Pressure recovery to a varying extent is common to all prosthetic heart valves including bioprostheses. Pressure recovery-related differences are usually small except in patients with bileaflet metallic prosthesis, wherein high-pressure local jets across central orifice have been documented since long back and also in patients with narrow aortic root. We describe two patients with normally functioning stented aortic bioprostheses with supra-annular design (EPIC SUPRA and PERIMOUNT MAGNA), wherein very high trans-prosthetic gradients and critically reduced estimated effective valve orifice areas in presence of normal aortic size were consistently recorded over long periods of follow-up. The valve leaflets, however had normal excursion, were thin, opened with a triangular or oblong shape and had expected geometric valve area (1.7 and 1.6cm2 respectively) measured by 3D trans-oesophageal echocardiographic planimetry. Pressure recovery upstream the valves accounted for 20% and 12% of total pressure gradients respectively. Dominant site for pressure drop was intra-valvular (75–85%). Such a phenomenon has not been reported in vivo for these two valve designs.

PROSTHESIS-PATIENT MISMATCH IN VALVULAR HEART DISEASE: AN EVALUATION OF ECHOCARDIOGRAPHIC FINDINGS

Guidelines for reporting echocardiographic studies in prosthetic heart valve patients have recently been published. Prothesis-patient mismatch (PPM) was first described in 1978 and is present when the effective orifice area (EOA) of an implanted surgical prosthetic valve is too small in relation to a patient’s body surface area (BSA). PPM remains a common occurrence and has been reported in the literature in up to 20-70% of AVR patients. This is concerning, since undersized prostheses relative to body size may result in higher transprosthetic gradients, worse hemodynamic function and adverse patient outcomes. We examined reporting trends in patients with prosthetic aortic and mitral valves at London Health Sciences Centre (LHSC)and St Joseph's Health Care, with particular focus on PPM in these patient populations. Patients with prosthetic aortic valve replacement (AVR) and/or mitral valve replacement (MVR) undergoing echocardiography between September 2003 and August 2013 were identified. Studies with complete patient data for whom PPM could be measured were included for further analysis. PPM was defined as EOA/BSA ≤ 0.85 cm2/m2 in the aortic position (0.65-0.85 cm2/m2 moderate, <0.65 cm2/m2 severe), and as ≤ 1.3 cm2/m2 in the mitral position. Demographic and echocardiographic parameters were evaluated. Overall 8901 studies from 3378 patients were identified (61% male; mean age 68 ± 13 years). Echocardiographic studies (mean 2.6 studies/patient) were performed in patients with AVR (6290, 71%), MVR (1904, 21%) or both (707, 8%). Complete data sets were obtained for 2391 AVR studies. PPM was present in 44% of AVR studies (severe in 3%). AVR patients with PPM were older at the time of valve replacement (71 vs. 63 years) and at follow-up (73 vs. 65 years), had greater body weight (86 vs. 81kg), larger BSA (1.97 vs. 1.92kg/m2), smaller left ventricular dimensions (47 vs. 49mm), LVOT (19 vs. 20mm) and aortic roots (30 vs. 32mm), with higher transprosthetic gradients (34 vs. 26mmHg) and lower Doppler velocity index (0.41 vs. 0.44) in comparison to patients without PPM (p<0.001 for all). PPM was more common in females (48% vs. 41%, p=0.002), in those with bioprosthetic AVR (56% vs. 9%, p<0.001), with concurrent CABG (52% vs. 39%, p<0.001) and without concurrent aortic root enlargement surgery (46% vs. 32%, p<0.001). The presence of PPM in AVR patients in our study population was common. Our data analysis identified patient subsets with a higher prevalence of PPM, which co-localized with indices of impaired cardiac performance.

Letter by House et al Regarding Article, “Prosthesis-Patient Mismatch in Bovine Pericardial Aortic Valves: Evaluation Using 3 Different Modalities and Associated Medium-Term Outcomes”

The proverbial gold standard for evaluating prosthesis-patient mismatch (PPM) is the effective orifice area index. This is attributable to the inverse relationship that exists between the effective orifice area index and mean gradient.1 Other tools have been promoted to identify PPM but have not withstood scrutiny.1 In a recent edition of Circulation: Cardiovascular Imaging , Chacko et al2 propose applying the American Society of Echocardiography guidelines for prosthetic valves to exclude the presence of PPM. In these guidelines, there is a useful algorithm for the evaluation of high transprosthetic gradients.3 This algorithm was specifically created to assist in the evaluation of aortic prostheses with elevated peak velocities exceeding 3 m/sec. A common pathogenesis of velocities exceeding 3 m/sec …

Impact of aortic prosthesis-patient mismatch on left ventricular mass regression.

Prostheses used for aortic valve replacement may be small in relation to body size, causing prosthesis-patient mismatch and delaying left ventricular mass regression. This study examined the effect of prosthesis-patient mismatch on regression of left ventricular mass after aortic valve replacement. We prospectively studied 96 patients undergoing aortic valve replacement between 2007 and 2012. Mean and peak gradients and indexed effective orifice area were measured by transthoracic echocardiography at 3 and 6 months postoperatively. Patient-prosthesis mismatch was defined as indexed effective orifice area ≤0.85 cm(2)·m(-2). Moderate prosthesis-patient mismatch was present in 25% of patients. There were no significant differences in demographic and operative data between patients with and without prosthesis-patient mismatch. Left ventricular dimensions, posterior wall thickness, transvalvular gradients, and left ventricular mass decreased significantly after aortic valve replacement in both groups. The interventricular septal diameter and left ventricular mass index regression, and left ventricular ejection fraction were better in patients without prosthesis-patient mismatch. There was a significant positive correlation between the postoperative indexed effective orifice area of each valve prosthesis and the rate of left ventricular mass regression. Prosthesis-patient mismatch leads to higher transprosthetic gradients and impaired left ventricular mass regression. A small-sized valve prosthesis does not necessarily result in prosthesis-patient mismatch, and may be perfectly adequate in patient with small body size.

High trans-prosthetic gradients and prosthetic aortic valve dysfunction: the need for an accurate and multimodality imaging approach

Abstract Introduction This report will review the role of echocardiography and other noninvasive methods in the differential diagnosis of high transprosthetic aortic gradients. New insights the pathophysiology of high transprosthetic gradients allowed more complete and accurate diagnosis of “functional” versus “organic” prosthetic “dysfunction indicating the strong potential of noninvasive methods. Specifically this report will review current applications of echocardiographic, Doppler and other noninvasive techniques in the evaluation of prosthetic valve mismatch and prosthetic obstruction. Moreover new insights the dynamics of discs and the Doppler characteristics of pathologic flows are discussed. Conclusions New insights the pathophysiology of prosthetic dysfunction, prosthesis mismatch and correlated prosthetic flows have significantly improved the understanding of the more correct diagnostic approach to patients with the suspicion of prosthetic dysfunction. In this regard transthoracic and transesophageal echo and Doppler echocardiography, cinefluoroscopy and other imaging modalities have a complementary diagnostic role.

Influence of prosthesis–patient mismatch on exercise-induced arrhythmias: A further aspect after aortic valve replacement

The influence of prosthesis-patient mismatch on outcome after aortic valve replacement is controversial. This study analyzed the impact of prosthesis-patient mismatch on survival, the extent of left ventricular mass, and physical capacity after replacement with a small-size prosthesis. A total of 157 patients who underwent valve replacement for pure aortic stenosis were reviewed. Late mortality, morbidity, left ventricular mass regression, transprosthetic gradient at rest and after exercise, exercise capacity, and occurrence of arrhythmias were evaluated. Prosthesis-patient mismatch, defined as an indexed effective orifice area of 0.75 cm(2)/m(2) or more, occurred in 96 (61.1%) patients and had no significant impact on early and late mortality. The only independent predictor of mortality was age greater than 65 years. At follow-up, multivariate analysis of prosthetic gradient at rest of 35 mm Hg end exercise capacity or more revealed that both these evidences were associated with high left ventricular mass (P < .001), female gender (P < .001), and follow-up time (P < .001). Arrhythmias occurred during exercise in 34.1% of patients (40/117). Multivariate analysis of occurrence of arrhythmias revealed that they were associated with high mean transprosthetic gradients: values of 50 mm Hg or more during exercise had 95% sensitivity and 72% specificity for predicting arrhythmias. Prosthesis-patient mismatch failed to demonstrate any significant impact on early and late mortality and morbidity and in left ventricular mass regression. High transprosthetic gradients influence exercise capacity and occurrence of arrhythmias.

Long-Term Follow-Up and Dobutamine Stress Echocardiography of 19-mm Prosthetic Heart Valves.

BACKGROUND: In patients with a small aortic root, the use of 19-mm valve prostheses for valve replacement is controversial because of the small orifice area of these valves. METHODS: To assess stress hemodynamics in patients with 19-mm valve prostheses, to find predictors of unfavorable hemodynamics, and to document the long-term follow-up, we examined 30 patients (age, 64 +/- 19 years; 27 women and 3 men; follow-up, 38 +/- 50 months) clinically and with the use of dobutamine stress echocardiography. A history was taken, and a physical examination was performed. At rest and during dobutamine stress, Doppler echocardiography was performed. RESULTS: At rest, transprosthetic gradients were moderately elevated with mean and peak gradients of 15 +/- 7 and 32 +/- 14 mmHg, and effective orifice areas were small (0.91 +/- 0.31 cm(2)). Gradients rose markedly during stress (mean, 37 +/- 14 mmHg; peak, 83 +/- 41 mmHg). Predictors of high transprosthetic gradients were larger body surface area, younger age, and valve type. Mean and peak gradients were lower with St. Jude Medical Hemodynamic Plus valves than with standard St. Jude Medical (P < 0.05) and other valves, and the effective orifice area was highest (1.07 +/- 0.29 cm(2); P < 0.05 versus standard St. Jude Medical) in this valve model. Sixty percent of patients developed significant dynamic subvalvular or intraventricular gradients (84 +/- 41 mmHg) during dobutamine stress. CONCLUSIONS: After aortic valve replacement with 19-mm prostheses in patients with a small aortic root, dobutamine stress leads to high transvalvular gradients, which are dependent on valve model, age, and body surface area. In addition, 60% of patients develop significant dynamic outflow obstructions. These findings and the persistence of some degree of exercise-induced symptoms in 70% of patients suggest that alternative surgical techniques should be considered if the size of the aortic annulus demands a 19-mm valve, especially if the patient seeks physical activity, is young, or is of larger body size.