Follow-up recatheterization after balloon aortic valvuloplasty. Mansfield Scientific Aortic Valvuloplasty Registry Investigators

Evolution of Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement emerged ≈20 years ago and changed the landscape of structural interventional cardiology. The first experiments in animal models provided proofs of the concept and the substrate for the first percutaneous valve implantation in patients. The initial promising results in a clinical setting drew the attention of the industry and of the scientific community, and an effort was made for the past 12 years to address the limitations of the technology, facilitate the procedure, minimize the risk of complications, and broaden the applications of transcatheter aortic valve replacement. This article reviews the evolution of transcatheter aortic valve replacement, presents the first steps in this field, cites the evidence from registries and clinical trials, highlights the limitations of this treatment, and discusses the future perspectives and the developments proposed to address the current pitfalls.

Clinical profile, treatment assignment and clinical outcome of patients with severe aortic stenosis not eligible to participate in a clinical trial of percutaneous aortic valve replacement

Patients with severe aortic stenosis and considered at high surgical risk or inoperable, and not eligible for a randomized clinical trial evaluating percutaneous aortic valve replacement (PAVR), were studied. Many of the patients referred to the study did not meet the inclusion criteria and/or had conditions listed in the exclusion criteria. These patients were then deferred to other treatment modalities. The study cohort consisted of 285 patients with severe aortic stenosis referred to participate in a clinical trial of PAVR. Patients were screened for eligibility on the basis of the protocol inclusion and exclusion criteria and deferred to other treatment modalities if they did not meet the enrollment criteria. Those patients were followed clinically by telephone contact or office visits. Of the 285 patients referred for PAVR, 216 (75.8%) were not included. The leading reasons for lack of eligibility were significant peripheral vascular disease in 50 (23.1%), Society of Thoracic Surgeons score <10% in 48 (22.9%), aortic valve area >0.8 cm(2) in 30 (13.9%), significant coronary artery disease in 25 (11.6%), and renal failure in 22 (10.2%). Sixty-nine of these patients (31.9%) were treated medically, 102 (47.2%) with balloon aortic valvuloplasty, and 45 (20.9%) with surgical aortic valve replacement. Major baseline characteristics were similar. Society of Thoracic Surgeons scores were lower in the surgical group compared with the medical and balloon aortic valvuloplasty groups (10.2 +/- 2.5 vs 12.8 +/- 3.3 vs 13.7 +/- 3.3, respectively, p <0.001). During a median follow-up period of 175.5 days (range 55.7 to 344.75), the mortality rate was higher in the balloon aortic valvuloplasty group compared with the medical and surgical aortic valve replacement groups (46 [45.1%] vs 22 [31.9%] vs 10 [22.2%], respectively, p = 0.01). In conclusion, high-risk patients with severe aortic stenosis who are deferred from PAVR often do poorly and incur high mortality rates, especially when treated with balloon valvuloplasty or medical therapy, while a loss of quality of life is apparent in those treated surgically.

Transapical transcatheter off-pump aortic valve implantation

Transapical aortic valve implantation (TA-AVI) is a new minimally invasive technique for beating-heart off-pump AVI in high-risk patients. The procedure involves antegrade AVI using an oversizing technique with direct access and accurate positioning of a stent based transcatheter xenograft. Procedural steps include placement of femoral arterial and venous access wires, anterolateral minithoracotomy, placement of an epicardial pacing wire and two apical purse-string sutures. Valve implantation is performed off-pump under fluoroscopic and echocardiographic guidance with rapid ventricular pacing. This new technology is a promising alternative for selected elderly high-risk patients and seems to be associated with good outcome and a minimal stroke risk.

Transcatheter aortic valve replacement in patients with critical aortic stenosis: rationale, device descriptions, early clinical experiences, and perspectives

The development of lesser invasive transcatheter techniques for aortic valve replacement (AVR) to treat high surgical risk patients with severe aortic stenosis (AS) has engendered controversy among traditional cardiovascular therapists. Presently, there are two catheter-based treatment systems (the Cribier-Edwards Aortic Bioprosthesis and the CoreValve Revalving System) utilizing either a balloon-expandable or a self-expanding stent (or cage) platform which unfolds a pericardial tissue valve within the displaced diseased aortic valve. After ex vivo durability testing and animal studies, several clinical registries with these transcatheter AVR systems in almost 300 patients worldwide have demonstrated the following: (1) good acute hemodynamic performance with reduction in mean aortic valve gradients to <10 mm Hg; (2) frequent para-valvular regurgitation, which has improved with self-expanding devices and the use of larger (26 mm) valve sizes; (3) acceptable periprocedural (30-day) mortality (<10%) with the newest generation devices and improved operator techniques. Enlightened interdisciplinary treatment teams incorporating surgeons, interventionalists, and medical therapists as well as rigorously conducted randomized clinical trials will be required to determine if these innovative transcatheter AVR approaches will represent a viable therapy for high-risk patients with severe AS in the future.

State of the art percutaneous intervention for the treatment of valvular heart disease: a review of the current technologies and ongoing research in the field of percutaneous valve replacement and repair

Technical developments in valvular intervention culminated in the first percutaneous valve replacement in the pulmonary position (2000) followed by replacement in the aortic position (2002). More recently, with the proven feasibility of percutaneous mitral valve repair, interventional cardiologists and cardiothoracic surgeons have begun to develop a new subspecialty dedicated to the percutaneous treatment of valvular disease. This review describes the clinical status of the current field, the applicability and limitations of new technologies, and the upcoming devices that will soon reach Phase I clinical trials.

Percutaneous aortic valve replacement and mitral valve repair

For mitral regurgitation and aortic valve disease warranting replacement, the surgical approach has been the mainstay therapy since the 1960s. Technological advances have provided potentially less invasive alternatives to surgery. Novel catheter-based techniques include aortic valve replacement with a valved stent, and devices aimed at reconfiguring the annulus or approximating a portion of the leaflets for mitral regurgitation. The main considerations regarding aortic valved stents include device anchoring and orientation, potential restriction of coronary flow, optimal method of delivery, ideal leaflet material, stent characteristics, and valve durability. The catheter-based approaches to mitral regurgitation are undergoing further experimental and clinical evaluations, and its success will be partially dependent on a thorough understanding of the underlying valvular pathology. Patient selection will be a critical component in the long-term efficacy of these new therapies. Close collaboration among the cardiovascular specialists and biomedical engineers will enable the development of safe and effective devices.

Is there any indication for aortic valvuloplasty in the elderly?

Elderly patients with severe symptomatic calcific aortic stenosis do poorly with medical management. The optimal treatment for this group of patients is surgical valve replacement. Balloon valvuloplasty may be useful as a bridge to aortic valve replacement in hemodynamically unstable patients, in patients undergoing emergent noncardiac surgery, and in patients with severe comorbidities who are too ill to undergo cardiac surgery. Balloon valvuloplasty often results in symptomatic improvement; however, the postvalvuloplasty valve area is usually <1.0 cm2, the major periprocedural complication rate is roughly 5%, and the 6-month restenosis rate is quite high. There is no evidence that balloon valvuloplasty alters the natural history of aortic stenosis, although no randomized study has been performed.

Balloon aortic valvuloplasty revisited: the role of the inoue balloon and transseptal antegrade approach

Percutaneous aortic balloon valvuloplasty (PABV) was developed to provide a less invasive alternative to aortic valve replacement. Despite initially favorable results, PABV has not produced reliable and durable outcomes. The Inoue balloon used for PABV via an antegrade transseptal approach may offer an improvement over the Mansfield balloons via the identical route. Thirteen consecutive patients with severe symptomatic aortic stenosis were referred for percutaneous aortic balloon valvuloplasty. All patients were considered unacceptably high-risk surgical candidates. Seven consecutive patients underwent antegrade transseptal PABV with Mansfield balloons and in the following six the Inoue balloon was used. The study group was characterized by advanced age (mean, 77) and multiple comorbid conditions (mean, 2.5/patient). Before PABV, the two groups did not differ with respect to age, mean NYHA class, LVEF, transaortic gradient, cardiac output, or aortic valve area. All patients had initial hemodynamic improvement. Complications included one stroke and one vascular injury. After valvuloplasty, cardiac output was not significantly changed. However, there was a significant decrease in aortic gradient and an increase in aortic valve area in both groups; the increase in aortic valve area was significantly greater in those treated with the Inoue balloon (P = 0. 039). Total follow-up mortality was high but appeared to be delayed in the Inoue group. The use of the Inoue balloon with an antegrade transseptal approach warrants further investigation as a preferred technique for PABV.

Combined PTCA and aortic valvuloplasty for acute myocardial infarction complicated by severe aortic stenosis and cardiogenic shock

Percutaneous aortic valvuloplasty (PAV) performed in patients with critical aortic stenosis has been shown to increase aortic valve area, decrease aortic valve gradient, and improve left ventricular function. However, the procedure is limited by rapid restenosis. Aortic valvuloplasty in the setting of critical aortic stenosis with cardiogenic shock can be a life-saving procedure, although morbidity and mortality remain high. We describe a patient with critical aortic stenosis who presented with an acute anterior myocardial infarction treated with primary angioplasty. Despite rapidly achieving patency of the culprit vessel, the patient spiraled into cardiogenic shock, which prompted an emergent PAV.

Comparison of aortic valve replacement and percutaneous aortic balloon valvuloplasty for elderly patients with aortic stenosis

The outcome of aortic balloon valvuloplasty (ABV) was compared with that of aortic valve replacement (AVR) in aortic stenosis (AS) patients more than 60 years old. The indications for ABV included low respiratory and renal function, cancer, the patient's refusal of surgery, and low daily activity. Twenty six patients underwent AVR and 13 underwent ABV. Initially, the AVR group was younger and more symptomatic than the ABV group. Two perioperative deaths occurred in the AVR group, while there were none in the ABV group. Twenty-four AVR patients and 12 ABV patients had a successful outcome, with remarkable pressure gradient reduction in both groups. In the follow-up, only 1 death and no cardiac events were detected in the AVR group (mean follow-up of 27 months), whereas 3 deaths, 6 heart failures, 2 repeated ABV, and 4 AVR were seen in the ABV group (mean follow-up of 10 months). The data showed that ABV was safer than AVR, but a higher rate of restenosis limited its efficacy. In the ABV group, a higher ratio of balloon size to aortic diameter correlated with longer event-free survival. We concluded that for elderly AS patients, ABV should be used only in those with high surgical risk as a palliative therapy or a bridge therapy to AVR, and AVR should be primarily recommended under rigid evaluation of the patient's physical status.

Balloon aortic valvuloplasty in adults: failure of procedure to improve long-term survival

OBJECTIVES

This study sought to determine the long-term outcome of adult patients undergoing percutaneous balloon aortic valvuloplasty.

BACKGROUND

Percutaneous balloon aortic valvuloplasty has been offered as an alternative to aortic valve replacement for selected patients with valvular aortic stenosis. Although balloon aortic valvuloplasty produces an immediate reduction in the transvalvular aortic gradient, a high incidence of restenosis frequently leads to recurrent symptoms. Therefore, it is unclear whether balloon aortic valvuloplasty impacts on the long-term outcome of these patients.

METHODS

Clinical, hemodynamic and echocardiographic data were collected at baseline in 165 patients undergoing balloon aortic valvuloplasty and examined for their ability to predict long-term outcome.

RESULTS

The median duration follow-up was 3.9 years (range 1 to 6). Ninety-nine percent follow-up was achieved. During this 6-year period, 152 patients (93%) died or underwent aortic valve replacement, and 99 (60%) died of cardiac-related causes. The probability of event-free survival (freedom from death, aortic valve replacement or repeat balloon aortic valvuloplasty) 1, 2 and 3 years after valvuloplasty was 40%, 19% and 6%, respectively. In contrast, the probability of survival 3 years after balloon aortic valvuloplasty in a subset of 42 patients who underwent subsequent aortic valve replacement was 84%. Survival after aortic valvuloplasty was poor regardless of the presenting symptom, but patients with New York Heart Association functional class IV congestive heart failure had events earliest. Univariable predictors of decreased event-free survival were younger age, advanced congestive heart failure symptoms, lower ejection fraction, elevated left ventricular end-diastolic pressure, presence of coronary artery disease and increased left ventricular internal diastolic diameter. Stepwise multivariable logistic regression analysis found that only younger age and a lower left ventricular ejection fraction contributed independent adverse prognostic information (chi-square 14.89, p = 0.0006).

CONCLUSIONS

Long-term event-free and actuarial survival after balloon aortic valvuloplasty is dismal and resembles the natural history of untreated aortic stenosis. Aortic valve replacement may be performed in selected subjects with good results. However, the prognosis for the remainder of patients who are not candidates for aortic valve replacement is particularly poor.

Successful aortic balloon valvuloplasty in critical aortic stenosis with shock

Emergency balloon valvuloplasty was performed in a 42 year old male with critical aortic stenosis, severe congestive heart failure, and shock. Hemodynamic and clinical improvement occurred and he underwent elective aortic valve replacement. Balloon aortic valvuloplasty may provide a "bridge" to aortic valve replacement in patients with critical aortic stenosis and shock.

The treatment of aortic stenosis: is valvuloplasty ever an alternative to surgery?

The desire to extend the principle of balloon angioplasty to cardiac valve disease is understandable and commendable. Aortic valvuloplasty is associated, however, with an excessive complication rate, as reported by the Mansfield Scientific Aortic Valvuloplasty Registry (20.5% overall, including a 4.9% death rate within 24 hours and an additional 2.6% rate within 7 days for a 7.5% 1-week mortality). In contrast, the operative mortality for aortic valve replacement now ranges from 3%-5%, with perioperative complications far less than the one in five associated with valvuloplasty. Even if the two procedures had equivalent morbidity and mortality rates, the high incidence of restenosis (30%-60% range at 6 months) for the balloon technique precludes its widespread use for aortic stenosis. Despite the poor mid- and long-term results for balloon valvuloplasty, the procedure may have limited application in some clinical situations. Indeed, there are patients with concomitant systemic illnesses or advanced age ( greater than 80 years) who would not be good surgical candidates. In particular, valvular balloon dilation may be useful in bridging a seriously ill patient to a condition more favorable for replacement therapy. With few exceptions, however, valve replacement remains the gold standard for treatment of adult aortic stenosis.

Percutaneous balloon aortic valvuloplasty. Acute and 30-day follow-up results in 674 patients from the NHLBI Balloon Valvuloplasty Registry

BACKGROUND

Percutaneous balloon aortic valvuloplasty has been used as a therapeutic option for relief of valvular stenosis. This study describes patients undergoing initial percutaneous aortic balloon valvuloplasty enrolled in the National Heart, Lung, and Blood Institute (NHLBI) Balloon Valvuloplasty Registry.

METHODS AND RESULTS

Extensive baseline procedural and postprocedural data were tabulated in 674 patients during a 24-month period. Functional status was captured using standard methods and an overall functional scoring system. Complications were defined and divided into procedural, acute (within 24 hours), in-hospital, and within 30 days of the procedure. The patient population was elderly and symptomatic, with 83% greater than 70 years of age. New York Heart Association functional class (FC) III or IV congestive heart failure (CHF) was present in 76%, syncope or presyncope was present in 34%, and Canadian Heart Association class III or IV angina was present in 23%. Using an overall functional scoring system (0-100), 54% exhibited scores less than 50. Comorbid disease was common. Forty-five percent possessed at least one serious noncardiac disability as a reason for valvuloplasty. Eighty percent of those seen by a cardiothoracic surgeon were believed inappropriate for aortic valve replacement. Hemodynamically, the aortic valve area increased from 0.5 +/- 0.2 cm2 to 0.8 +/- 0.3 cm2 (p less than 0.0001), accompanied by a fall in mean and peak aortic valve gradient from 55 +/- 21 and 65 +/- 28 mm Hg to 29 +/- 13 and 31 +/- 18 mm Hg, respectively (both p less than 0.0001). Small but significant increases were observed in cardiac output, heart rate, and mean aortic pressure with minor declines in the pulmonary artery (PA) systolic and left ventricular (LV) end-diastolic pressure. One hundred sixty-seven (25%) experienced at least one significant complication within 24 hours, and 211 (31%) experienced a significant complication before discharge. Complications before hospital discharge included the need for transfusion (23%), vascular surgery (7%), cerebrovascular accident (3%), other systemic embolus (2%), myocardial infarction (2%), acute tubular necrosis (1%), or cardiac surgery (1%). Seventeen (3%) patients died during the procedure; 16 of those were due to cardiac causes. By hospital discharge, there was an additional 52 total deaths; 37 were due to cardiovascular causes. Between hospital discharge and 30 days, 23 additional deaths occurred; 18 were due to cardiac disease. At 30 days, therefore, there was a grand total of 92 (14%) deaths; 71 (11%) were due to cardiovascular-related causes. Univariate and logistic regression analysis of mortality revealed that death was most frequent in patients suffering multiorgan failure and poor LV systolic function. Thirty-day mortality was associated with a predefined high-risk subset of hypotension and NYHA class IV CHF (risk ratio, 4.4), blood urea nitrogen (BUN) greater than 30 mg/dl (risk ratio, 3.7), use of an antiarrhythmic (risk ratio, 2.9), and cardiac output less than 3.0 l/min (risk ratio, 2.4). Of the survivors (86%) at 30 days, symptomatic improvement was generally present. Seventy-five percent experienced at least one functional class improvement in CHF, and 53% experienced at least a quartile improvement in overall functional status score.

CONCLUSIONS

These data reveal that percutaneous aortic balloon valvuloplasty in an elderly and debilitated population can be done with low mortality but substantial morbidity. Mortality is greatest in patients with multiorgan failure resulting from poor cardiac output. In patients with reasonably preserved LV function who are otherwise inappropriate surgical candidates because of comorbid factors, survival and early improvement in symptomatic status are frequently observed after percutaneous aortic valvuloplasty.

Demonstration of postvalvuloplasty hemodynamic improvement in aortic stenosis based on Doppler measurement of valvular resistance

It was recently suggested that valvular resistance, defined as the pressure gradient/flow rate ratio, may better depict the hemodynamic impairment in aortic stenosis than does valve area. The relation between aortic valve resistance and left ventricular mechanics was studied with Doppler echocardiography in 13 patients (mean age 85 years) with severe aortic stenosis who underwent percutaneous balloon valvuloplasty. The Doppler-estimated peak valvular resistance, defined as the ratio of peak transvalvular pressure gradient to peak valvular flow rate, decreased from 510 +/- 190 dynes.s.cm-5 before valvuloplasty to 300 +/- 110 dynes.s.cm-5 after the procedure (p = 0.0001). There was a close linear relation between valvular resistance measured at catheterization and Doppler-derived peak valvular resistance (r = 0.91). After valvuloplasty, left ventricular ejection fraction increased from 53 +/- 13% to 62 +/- 11% (p = 0.0001). The percent increase in ejection fraction was linearly related to the percent decrease in end-systolic wall stress (r = 0.56), which was in turn related to the percent decrease in peak valvular resistance (r = 0.75). No such linear relation existed between the percent changes in valve area and those in end-systolic wall stress. In conclusion, hemodynamic improvement after valvuloplasty is more closely related to changes in valvular resistance than to changes in valvular area. It is suggested that valvular resistance can be estimated accurately by Doppler echocardiography with use of a simple method and should be a primary consideration in assessing the hemodynamics of aortic stenosis.