From pressure overload to volume overload: aortic regurgitation after transcatheter aortic valve implantation

Severe aortic valve stenosis is a common valvular heart disease that is characterized by left ventricular (LV) pressure overload. A lasting effect of pressure overload is LV remodeling, accompanied by concentric hypertrophy and increased myocardial stiffness. Transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgical aortic valve replacement for patients with severe symptomatic aortic valve stenosis and high surgical risk. Although TAVI has favorable hemodynamic performance, aortic valve regurgitation (AR) is the most frequent complication because of the specific technique used for implantation of transcatheter valves. During implantation, the calcified native valve is pushed aside, and the prosthesis usually achieves only an incomplete prosthesis apposition. As a consequence, the reported prevalence of moderate and severe AR after TAVI is 6% to 21%, which is considerably higher than that after a surgical valve replacement. Although mild AR probably has minor hemodynamic effects, even moderate AR might result in serious consequences. In moderate and severe AR after TAVI, a normal-sized LV with increased myocardial stiffness has been exposed to volume overload. Because the noncompliant LV is unable to raise end-diastolic volume, the end-diastolic pressure increases, and the forward stroke volume decreases. In recent years, an increasing number of patients have successfully undergone TAVI. Despite encouraging overall results, a substantial number of patients receive neither symptomatic nor prognostic benefits from TAVI. Aortic valve regurgitation has been considered a potential contributor to morbidity and mortality after TAVI. Therefore, various strategies and improvements in valve designs are mandatory to reduce the prevalence of AR after TAVI.     

Assessment of aortic valve disease——a clinician oriented review

Aortic valve disease [aortic stenosis(AS) and aortic regurgitation(AR)] represents an important global healthproblem; when severe, aortic valve disease carries poor prognosis. For AS, aortic valve replacement, either surgical or interventional, may provide definite treatment in carefully selected patients. For AR, valve surgery(either replacement or-in selected cases-aortic valve repair) remains the gold standard of care. To properly identify those patients who are candidates for surgery, the clinician has to carefully assess the severity of valve disease with an understanding of the potential pitfalls involved in these assessments. This review focuses on the practical issues concerning the evaluation of patients with AS and AR from a general cardiologist's perspective. The most important issues regarding the documentation of the severity of AS and AR are summarized. More specific issues, such as the role of stress echocardiography, other imaging techniques and details regarding the treatment options(medical, surgical, or interventional), are mentioned briefly.     

A heart valve dedicated for aortic regurgitation: Review of technology and early clinical experience with the transfemoral Trilogy system

Aortic regurgitation (AR) is associated with morbidity and premature mortality. Surgical aortic valve replacement is not an option for many patients due to an adverse surgical risk profile, whilst transcatheter aortic valve implantation with most available prostheses has demonstrated suboptimal implantation success and outcomes. The JenaValve Trilogy™ system provides an attractive solution for such patients as it utilizes clips that directly attach onto the native valve leaflets to anchor. Initially designed for transapical delivery, the current transfemoral delivery system is under investigation in the United States and approved for aortic stenosis and regurgitation in Europe. We present an expert review on the technical aspects of the Trilogy system, provide a guide for implantation, discuss the available evidence for the technology and provide illustrative case examples.     

Quadricuspid aortic valve associated with severe aortic regurgitation

A 57-year old man with severe aortic regurgitation was found to have a quadricuspid aortic valve. Aortic valve replacement was performed successfully with a St. Jude Medical prosthetic valve. On histological examination, the resected cusps showed fibrotic thickening with calcification.     

Aortic valve disease: a practical clinical approach

The diagnosis and treatment of aortic valve disease can be challenging for the clinician. Aortic regurgitation (AR) may be evaluated with Doppler echocardiography or catheterization. Medical therapy consists of vasodilators. Surgery may be appropriate for patients with symptoms, left ventricular dilatation or diminished left ventricle systolic function. Aortic stenosis (AS) can be evaluated with the same modalities as AR. There is evidence that statin therapy may slow the progression of AS. Contrary to conventional wisdom, vasodilators are safe and effective in certain patients. Surgical valve replacement is performed for symptoms and in certain asymptomatic patients.     

An exceptional form of congenitally bicuspid aortic valve resulting in pure aortic regurgitation

A case with an exceptional form of congenitally bicuspid aortic valve is described. A fibrous strand connected to the supra-aortic ridge supported the conjoined cusp, and severe pure aortic regurgitation was present although the fibrous strand remained intact. Aortic valve replacement was successfully performed.     

The natural history of aortic valve disease after mitral valve surgery

OBJECTIVES

The present study evaluates the long-term course of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery.

BACKGROUND

Little is known about the natural history of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition there is no firm policy regarding the appropriate treatment of mild aortic valve disease while replacing the mitral valve.

METHODS

One-hundred thirty-one patients (44 male, 87 female; mean age 61 ± 13 yr, range 35 to 89) were followed after mitral valve surgery for a mean period of 13 ± 7 years. All patients had rheumatic heart disease. Aortic valve function was assessed preoperatively by cardiac catheterization and during follow-up by transthoracic echocardiography.

RESULTS

At the time of mitral valve surgery, 59 patients (45%) had mild aortic valve disease: 7 (5%) aortic stenosis (AS), 58 (44%) aortic regurgitation (AR). At the end of follow-up, 96 patients (73%) had aortic valve disease: 33 AS (mild or moderate except in two cases) and 90 AR (mild or moderate except in one case). Among patients without aortic valve disease at the time of the mitral valve surgery, only three patients developed significant aortic valve disease after 25 years of follow-up procedures. Disease progression was noted in three of the seven patients with AS (2 to severe) and in six of the fifty eight with AR (1 to severe). Fifty two (90%) with mild AR remained stable after a mean follow-up period of 16 years. In only three patients (2%) the aortic valve disease progressed significantly after 9, 17 and 22 years. In only six patients of the entire cohort (5%), aortic valve replacement was needed after a mean period of 21 years (range 15 to 33). In four of them the primary indication for the second surgery was dysfunction of the prosthetic mitral valve.

CONCLUSIONS

Our findings indicate that, among patients with rheumatic heart disease, a considerable number of patients have mild aortic valve disease at the time of mitral valve surgery. Yet most do not progress to severe disease, and aortic valve replacement is rarely needed after a long follow-up period. Thus, prophylactic valve replacement is not indicated in these cases.     

Differences in Coronary Blood Flow in Aortic Regurgitation and Systemic Arterial Hypertension Have Implications for Diastolic Blood Pressure Targets: A Systematic Review and Meta‐Analysis

The objective was to evaluate coronary blood flow (CBF) in patients with systemic arterial hypertension (HTN) and to compare it with CBF in patients with aortic regurgitation (AR). A systematic literature search was conducted using the reference terms “coronary blood flow” and either “aortic regurgitation” or “hypertension.” The selection criteria included CBF measurement in a concomitant control group, except studies evaluating CBF with aortic‐valve replacement surgery. Twenty‐two studies met the inclusion criteria. There were 318 persons with HTN, with 185 controls; and 102 persons with AR, with 144 controls. Despite an overall increase in CBF in HTN, CBF per gram of left ventricular mass was significantly (P < 0.0001) reduced. In contrast, CBF per gram of left ventricular mass was significantly (P = 0.004) increased in AR. Aortic regurgitation was associated with a significant (P < 0.0001) increase in CBF during systole and away from diastole, in contrast to persons with HTN. Aortic‐valve replacement reversed the increase in systolic CBF. These data suggest that patients with HTN are more vulnerable than patients with AR to lower diastolic blood pressure (DBP), because resting CBF is compromised in HTN. Furthermore, patients with HTN may not compensate for DBP reductions by shifting CBF to systole, such as can occur with the low DBP in AR. Lower DBP in patients with AR cannot be used to justify treating patients with HTN to similar DBP because of the dramatic differences in CBF between the 2 conditions.     

Valvular and perivalvular abnormalities in end-stage renal disease

Valvular and perivalvular involvement in end-stage renal disease (ESRD) is most commonly manifested as mitral annular calcification and aortic valve calcification. Both mitral and aortic valve calcification (MAC) occur more frequently and at younger age in those with ESRD than in those with normal renal function. Aortic valve calcification progresses to aortic stenosis more commonly and at a more accelerated rate than in the general population. Altered calcium and phosphate metabolism are thought to predispose to these valvular and perivalvular abnormalities. No treatment is necessary for MAC unless severe mitral regurgitation or stenosis occur (both are rare). Mitral valve repair or replacement and aortic valve replacement are indicated for severe symptomatic valve stenosis or regurgitation, albeit at a higher risk than in those with normal renal function. Infective endocarditis may complicate MAC or aortic stenosis in patients with ESRD and is associated with a high mortality rate in such patients.     

Pivotal role of aortic valve area calculation by the continuity equation for Doppler assessment of aortic stenosis in patients with combined aortic stenosis and regurgitation

Aortic regurgitation (AR) may result in overestimation of the aortic pressure gradient by continuous wave Doppler in patients with mixed aortic valve disease. However, few data are available regarding the effect of AR on noninvasive estimates of aortic valve area by the continuity equation. Therefore, 25 patients with angiographically documented severe AR and peak systolic aortic velocities of greater than 2.5 m/s were studied by continuous wave Doppler to determine the accuracy of pressure gradient and aortic valve area calculations in assessing the severity of aortic stenosis (AS) in this patient population. Peak instantaneous pressure gradient showed a general correlation to but was overestimated by Doppler (r = 0.78, Doppler = 0.70 catheter + 19.9) and did not predict aortic valve area. Mean pressure gradient by Doppler correlated more closely with catheter mean gradient (r = 0.86, Doppler = 0.79 catheter + 6.1) but was a poor predictor of the severity of AS. In contrast, the continuity equation accurately predicted the aortic valve area by catheterization (r = 0.92, Doppler = 0.89 catheter -0.08). Thus, the continuity equation provides a reliable estimate of aortic valve area in patients with severe AR and should be used to evaluate the extent of AS in such patients when high systolic aortic velocities are present.     

Multiple pseudo-abscesses following aortic valve replacement.

Prosthetic aortic valve endocarditis is associated with valve ring abscess, conduction abnormalities and a grave prognosis. Aortic root abscess is a serious complication of infective endocarditis with high mortality. We report a case of a patient who had echocardiographic features resembling aortic root abscess along with severe aortic regurgitation, 6 weeks following aortic valve replacement. Valvular dehiscence led to perivalvular abscess like appearance. Infective endocarditis was exluded. He underwent a successful redo aortic valve surgery with slow recovery.     

Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair

OBJECTIVES: The purpose of this study was to use transesophageal echocardiography (TEE) to define the mechanisms of aortic regurgitation (AR) in acute type A aortic dissection so as to assist the surgeon in identifying patients with mechanisms of AR suitable for valve preservation. BACKGROUND: Significant AR frequently complicates acute type A aortic dissection necessitating either aortic valve repair or replacement at the time of aortic surgery. Although direct surgical inspection can identify intrinsically normal leaflets suitable for repair, it is preferable for the surgeon to correlate aortic valve function with the anatomy prior to thoracotomy. METHODS: We studied 50 consecutive patients with acute type A aortic dissection in whom preoperative TEE findings were considered by the surgeons in planning aortic valve surgery. Six patients did not undergo surgery (noncandidacy or refusal) and one patient had had a prior aortic valve replacement and therefore was excluded from the analysis. RESULTS: Twenty-seven patients had no or minimal AR and 22 had moderate or severe AR. In all, there were 16 with intrinsically normal leaflets who had AR due to one or more correctable aortic valve lesion: incomplete leaflet closure due to leaflet tethering in a dilated aortic root in 7; leaflet prolapse due to disrupted leaflet attachments in 8; and dissection flap prolapse through the aortic valve orifice in 5. Of these 16 patients, 15 had successful aortic valve repair whereas just 1 underwent aortic valve replacement after a complicated intraoperative course (unrelated to the aortic valve). Nine patients underwent aortic valve replacement for nonrepairable abnormalities, including Marfan's syndrome in four, bicuspid aortic valve in four, and aortitis in one. In patients undergoing aortic valve repair, follow-up transthoracic echocardiography at a median of three months revealed no or minimal residual AR, and clinical follow-up at a median of 23 months showed that none required aortic valve replacement. CONCLUSIONS: When significant AR complicates acute type A aortic dissection, TEE can define the severity and mechanisms of AR and can assist the surgeon in identifying patients in whom valve repair is likely to be successful.     

Aortic valve regurgitation in alkaptonuria

Aortic valve lesions associated with alkaptonuria tend mostly to be due to aortic valve stenosis, while aortic valve regurgitation is only rarely observed. Herein, a case is reported of severe aortic valve regurgitation and a fibrous strand in a patient with alkaptonuria. A 65-year-old male, with a history of inferior myocardial infarction, presented with symptoms of congestive heart failure. Alkaptonuria was diagnosed based on urine coloration, skin pigmentation and ochronotic arthropathy in the vertebrae and hip. Grade IV aortic valve regurgitation with mild aortic valve stenosis and occlusive disease in the right coronary artery indicated a need for aortic valve replacement and coronary artery bypass grafting. Sclerotic change in the cusps, and shrinkage of the non-coronary cusp, impeded normal coaptation of the aortic valve, and the left-coronary cusp also had a fibrous strand suspending the free margin of the cusp from the aortic wall just above the commissure. The sclerotic change in the cusps, and shrinkage of the non-coronary cusp, appeared to be the causative lesion of aortic valve regurgitation, implying that cardiovascular ochronosis may cause aortic valve regurgitation.     

保留主动脉瓣主动脉根部替换术的临床应用评价

目的评价保留自身主动脉瓣的主动脉根部替换的可行性和疗效。方法自1998年1月至2004年9月,对我院24例主动脉病变导致主动脉瓣关闭不全但瓣膜本身无明显异常的患者,实施了保留主动脉瓣的主动脉根部替换术,并术后随访观察主动脉瓣反流和心功能改善情况。结果全组无住院死亡。除1例仍为中度反流外,术后主动脉瓣反流均明显改善。随访中有2例非手术相关死亡,无主动脉瓣反流需再次手术者。全组心功能恢复满意。结论主动脉根部替换手术时,对由于主动脉根部瘤或升主动脉瘤导致的主动脉瓣反流者,可优选采用保留主动脉瓣的主动脉根部替换术。     

Prevalence and clinical significance of aortic valve prolapse

The prevalence and clinical significance of aortic valve prolapse were determined prospectively in 2000 consecutive patients undergoing routine clinical cross sectional echocardiography. Two hundred and twelve patients were excluded because the aortic cusps were not adequately visualised. Aortic valve prolapse was defined as downward displacement of cuspal material below a line joining the points of attachment of the aortic valve leaflets. Twenty four cases of aortic valve prolapse (1.2%) were identified. The patients were aged 12-64 years and nine were women. All had underlying valvar heart disease and the commonest lesion (in 11 cases) was prolapse of the larger cusp in bicuspid valves. Aortic valve prolapse was seen in four patients with mitral valve prolapse (two with severe regurgitation), one of whom had marfanoid aortic root dilatation. The remaining examples of aortic prolapse were seen in patients with various disorders including one with pulmonary atresia, two with aortic root disease (one with dissection and one with idiopathic dilatation), and one case of severe mitral regurgitation. Valves destroyed by infective endocarditis were seen in two cases. Aortic valve prolapse may be detected in various cardiac disorders and does not imply the presence of aortic regurgitation, but when bicuspid aortic valves are present it may well be important in producing such regurgitation. Although aortic valve prolapse may be associated with severe forms of mitral valve prolapse, these patients rarely have aortic regurgitation.     

Valve-Sparing Aortic Root Replacement and Tricuspidization in a Patient with an Asymmetric Bicuspid Aortic Valve

Aortic valve replacement is the standard surgical procedure for severe aortic regurgitation. Due to advances over the past decade, there have been substantial improvements in aortic root graft design, in aortic valve repair techniques, and in the understanding of valvular function in the remodeled aortic root. Herein, we describe the case of a dyspneic patient with an asymmetric bicuspid aortic valve who underwent valve-sparing aortic root replacement and tricuspidization. The patient subsequently resumed strenuous physical activity and was asymptomatic 2 years after the operation.Key words: Aortic diseases/pathology/surgery/ultrasonography, aortic valve/abnormalities, aortic valve insufficiency/complications/surgery/ultrasonography, cardiac surgical procedures/methods, suture techniques, treatment outcomeThe conventional surgery for severe aortic regurgitation has been aortic valve replacement. This procedure, however, may soon become obsolete due to advances in aortic valve repair. Over the past decade, there have been substantial improvements in aortic root graft design, in aortic valve repair technique, and in the understanding of valvular function in the remodeled aortic root.^1–7 Herein, we describe the case of a patient with complex aortic root disease who underwent surgical repair.     

Evaluation and management of aortic valve and root disease

Opinion statement Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology’s impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.     

Prevalence and clinical significance of aortic valve prolapse.

The prevalence and clinical significance of aortic valve prolapse were determined prospectively in 2000 consecutive patients undergoing routine clinical cross sectional echocardiography. Two hundred and twelve patients were excluded because the aortic cusps were not adequately visualised. Aortic valve prolapse was defined as downward displacement of cuspal material below a line joining the points of attachment of the aortic valve leaflets. Twenty four cases of aortic valve prolapse (1.2%) were identified. The patients were aged 12-64 years and nine were women. All had underlying valvar heart disease and the commonest lesion (in 11 cases) was prolapse of the larger cusp in bicuspid valves. Aortic valve prolapse was seen in four patients with mitral valve prolapse (two with severe regurgitation), one of whom had marfanoid aortic root dilatation. The remaining examples of aortic prolapse were seen in patients with various disorders including one with pulmonary atresia, two with aortic root disease (one with dissection and one with idiopathic dilatation), and one case of severe mitral regurgitation. Valves destroyed by infective endocarditis were seen in two cases. Aortic valve prolapse may be detected in various cardiac disorders and does not imply the presence of aortic regurgitation, but when bicuspid aortic valves are present it may well be important in producing such regurgitation. Although aortic valve prolapse may be associated with severe forms of mitral valve prolapse, these patients rarely have aortic regurgitation.     

Is balloon aortic valvuloplasty safe in patients with significant aortic valve regurgitation?

Objectives: To assess safety and effectiveness of balloon aortic valvuloplasty (BAV) in patients with symptomatic severe aortic stenosis (AS) and significant aortic regurgitation. Background: BAV is a palliative procedure that has possibly been underused in patients with symptomatic AS not suitable for surgical aortic valve replacement or transcatheter aortic valve implantation. Significant aortic regurgitation is commonly perceived as a contraindication to BAV. Methods: Among 416 consecutive patients undergoing BAV at our Institution, 73 patients showed moderate or severe AR before the procedure. Demographics and baseline characteristics, as well as in‐hospital clinical outcome, have been prospectively collected in a dedicated database. Transthoracic echocardiography was regularly performed in all patients undergoing BAV before the procedure and at hospital discharge. Results: Patients had a high‐risk profile, confirmed by advanced age (77.2 ± 11.8 years) and important comorbidity (logistic Euroscore 26.5 ± 16.3%). Advanced heart failure was present in 73.9%. Indication to BAV was cardiogenic shock in 9.6%, palliation in 31.5%, bridge in 58.9% of the patients. BAV was performed with standard retrograde approach. Aortic valve area increased from 0.62 ± 0.15 cm² at baseline to 0.83 ± 0.17 cm² before discharge (P < 0.001). The degree of AR was improved or unchanged in 65 patients (89%). In‐hospital mortality was 6.9%, mainly limited to terminal patients. Symptomatic status at discharge was improved in all surviving patients. Acute AR occurred in seven patients; in five of them it was successfully resolved in the catheterization laboratory. Conclusions: When clinically indicated, BAV can be safely performed in patients with combined aortic stenosis and significant aortic regurgitation. © 2011 Wiley Periodicals, Inc.