Repeated Aortic Balloon Valvuloplasty in Elderly Patients With Aortic Stenosis Who Are Not Candidates for Definitive Treatment

Abstract: Aims. A sizable group of patients with symptomatic aortic stenosis can undergo neither surgical aortic valve replacement nor transcatheter aortic valve implantation. The aim of this study was to assess the potential role of repeated balloon aortic valvuloplasty (BAV) in these patients. Methods. Within our local prospective BAV registry, we retrospectively selected 105 patients who underwent ≥2 BAV procedures between 2005 and 2012 because of persisting contraindications to definitive treatment after first BAV. In-hospital outcome and incidence of adverse events at 1, 2, and 3 years were assessed. Mean age was 84 ± 6 years, mean logistic EuroSCORE was 23.6 ± 13.4%. Results. No intraprocedural deaths occurred. In-hospital events for the 224 BAV procedures were: myocardial infarction, 4%; stroke, 0.9%; vascular complications, 8% (1.8% major); and bleedings, 5.9% (life threatening, 0.9%; major, 1.8%). Acute aortic regurgitation occurred in 6 cases and was always resolved during procedures. Median follow-up was 785 days. Second BAVs showed fewer vascular complications (P<.001) and bleedings (P<.001). Bleedings (odds ratio [OR], 6.88; 95% confidence interval [CI], 1.58-29.88) and vascular complications (OR, 4.8; 95% CI, 1.19-19.31) occurring after the first procedure were independent predictors for subsequent adverse events. All-cause mortality at 1, 2, and 3 years was 15.2%, 41.3%, and 57.2%. Hospital readmission for heart failure was 40.7% at 1-year follow-up, 61.7% at 2-year follow-up, and 77.6% at 3-year follow-up. Conclusion. BAV is associated with poor long-term clinical outcome. However, when no other therapeutic options are feasible, a strategy of repeated palliative BAV appears to be safe and is potentially associated with improved clinical outcomes.

J INVASIVE CARDIOL 2015;27(12):E277-E284. Epub 2015 September 15.

Key words: aortic stenosis, balloon aortic valvuloplasty, valve restenosis, heart failure

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Balloon aortic valvuloplasty (BAV) was initially proposed as an alternative to surgical aortic valve replacement (AVR) in patients with severe aortic valve stenosis.¹ However, the initial enthusiasm quickly vanished after several studies showed a high incidence of early restenosis and symptom recurrence and a high rate of periprocedural complications.^2-4 Hence, BAV was nearly abandoned and used only occasionally as palliative treatment for severely symptomatic, inoperable patients.

In the last few years, transcatheter aortic valve implantation (TAVI) has emerged as a less invasive and very effective therapeutic option for inoperable patients or patients with high surgical risk.^5,6 Despite the new therapeutic possibilities, a sizable percentage of patients with severe aortic stenosis are not suitable for either AVR or TAVI, mainly because of coexisting illnesses.⁷ In these patients, BAV could be useful as a stand-alone treatment to reduce symptoms, or as a bridge to definitive treatment in selected patients with temporary contraindications to TAVI or AVR.^7,8 Consistently, as reported by many investigators, BAV procedures have increased exponentially since TAVI became available in clinical practice (Figure 1). According to current guidelines on valvular heart disease, in fact, BAV may be considered as a bridge to surgery or TAVI in hemodynamically unstable patients, and as a palliative measure in selected individuals when surgery and TAVI are contraindicated.⁹

The aim of this study was to describe the role of palliative BAV, focusing on the repeatability of the procedure in patients who are not candidates for surgical or transcatheter treatment.

Methods

Study design. This is a retrospective study based on the prospective BAV registry of the Institute of Cardiology of the University Hospital in Bologna, Italy. Every consecutive patient undergoing BAV or TAVI at our institution is enrolled in the database, which currently counts over 1200 BAVs and 215 TAVIs from 2000 until the end of 2013.

Patients. Among BAV patients, we selected those who underwent ≥2 BAV procedures from January 1, 2005 to December 31, 2012. A population of 105 patients (mean age, 84 ± 6 years) was identified irrespective of the primary indication for the procedure; in-hospital outcomes for all procedures and 1, 2, and 3-year outcomes after the first BAV procedure were assessed.

Procedure. All procedures were performed with the Cristal balloon (Balt) using the standard retrograde technique. A low-dose heparin bolus was administered after sheath insertion in all patients (40-50 IU/kg). As per local protocol, in the vast majority of cases, BAV was initiated with a 20-mm diameter balloon unless annular diameter measured by transthoracic echocardiography was >24 mm or <18 mm. This choice is based on the fact that the semicompliant balloon material enables some variation of diameter above or below the nominal level. Thus, balloon diameter was modulated with manual inflation in order to achieve a balloon-to-annulus ratio of 1:1, confirmed by the complete sealing of the valvular orifice and aortic pulse abrogation in the absence of fast pacing. The objective was to perform three manual inflations with complete abrogation of aortic pulse for a few seconds. If this could not be achieved with the first balloon, a larger-size balloon was used. The procedure was terminated if one of the following occurred: three dilations with complete pulse abrogation regardless of hemodynamic results; balloon rupture or exchange and evidence of mean transaortic gradient (TAG) reduction ≥50%; or acute severe aortic regurgitation. Access-site hemostasis was accomplished using the 8 Fr Angio-Seal device (St. Jude Medical), application of a compressive bandage, and bed rest for 24 hours.

Indication to BAV was always decided by a heart team, and was post hoc categorized in the following groups: (1) bridge to TAVI or bridge to AVR: patients suitable for TAVI or AVR, who underwent BAV as a bridge to definitive treatment because of severe symptoms, hemodynamic instability, or temporary contraindications; (2) bridge to non-cardiac surgery: patients who needed non-cardiac surgery or interventions at high cardiac risk because of aortic stenosis; 3) cardiogenic shock: emergency procedure in patients with cardiogenic shock due to aortic stenosis; or (4) palliative: patients who were not suitable for any definitive treatment.

Definitions. Severe aortic stenosis was defined as aortic valve area (AVA) <1 cm² and AVA indexed <0.6 cm²/m² assessed by echocardiography.⁹Symptomatic status was classified based on the presence of syncope, angina, and/or dyspnea. AVA was reassessed during left catheterization by the Gorlin formula and peak-to-peak and mean TAGs were measured before dilation. Post-BAV AVA and aortic valve gradients were compared with those obtained at baseline. If necessary, coronary angiography and percutaneous treatment of coronary lesions were performed before the procedure. Peripheral vascular disease included a history of intermittent claudication, previous peripheral vascular surgery, or a documented peripheral arterial stenosis >70%. Chronic renal insufficiency was considered a glomerular filtration rate <60 mL/min calculated by the Cockcroft-Gault formula.¹⁰Chronic obstructive pulmonary disease was identified by long-term use of bronchodilators, steroids, or oxygen for lung disease. Pulmonary hypertension was indicated by a systolic pulmonary artery pressure ≥35 mm Hg as estimated by ultrasound. Cardiogenic shock was defined as the presence of hypotension with a systolic blood pressure <100 mm Hg associated with clinical signs of poor tissue perfusion (eg, oliguria, cyanosis, cool extremities). Neurological dysfunction was defined on the basis of compromised ambulation, day-to-day functions, or cognitive decline.  Patient clinical functional status was defined using the New York Heart Association parameters. Myocardial infarction was defined as a rise in creatine kinase level to >2x the upper normal limit with an increased creatine kinase-MB, elevated high-sensitivity troponin-T values with variations more than 20% or 50% from baseline in the subsequent blood tests at 3 and 6 hours, or newly developed Q-waves. Stroke was diagnosed by a neurologist on the basis of neurological signs or symptoms consistent with stroke and a positive neuroimaging study. Bleeding and vascular complications were assessed as defined by the Vascular Academic Research Consortium 2.¹¹

Study endpoints. The objective of the study was to evaluate the incidence of death, myocardial infarction, stroke, rehospitalization for heart failure, bleedings, and vascular complications during in-hospital stays and up to 3 years of follow-up after the first BAV. A composite in-hospital endpoint including death, myocardial infarction, vascular complications, and bleedings was assessed for the readmissions for repeat BAV.

Statistical analysis. Continuous variables were expressed as mean ± standard deviation or median ± interquartile range and compared with Student’s t-test or Wilcoxon signed-rank test in case of significant departures from normality assumptions. Categorical variables were compared using Pearson’s Chi-square test. All tests were two-sided and statistical significance was defined as P<.05. Cumulative event rates were estimated using the Kaplan-Meier method and compared with the log-rank test. Patients were censored at the time of the last contact. For patients who underwent TAVI or AVR following BAV, the last follow-up was considered the day of these procedures. A univariate logistic regression analysis was used to examine the association of events that occurred during hospitalization for the first BAV with a composite in-hospital endpoint for the second BAV admission.

Results

From January 1, 2005 to December 31, 2012, a total of 105 patients underwent ≥2 BAV procedures at our center because of severe symptomatic aortic stenosis, for a total of 224 procedures (up to 5 procedures/patient). Baseline patient demographics and clinical characteristics are provided in Table 1. Patients undergoing BAV were 84 ± 6 years old, with a slight predominance of women (55.2%) and a high prevalence of comorbidities. The average logistic EuroSCORE was 23.6 ± 13.4%. The vast majority of our patients showed chronic kidney disease, with severe impairment (glomerular filtration rate ≤30 mL/min) in 23.8%. Indication for the first BAV was: bridge to TAVI in 38 patients (36.2%); bridge to AVR in 6 patients (5.7%); bridge to non-cardiac surgery in 1 patient (0.9%); cardiogenic shock in 2 patients (1.9%); and palliative procedure in 58 patients (55.2%). Patients in the palliative group were very old (32 patients >85 years; 9 patients >90 years) with multiple comorbidities (for example, 23 had severe kidney failure, 9 had left ventricular ejection fraction <30%, 26 had logistic EuroSCORE >25%). Reasons to opt for a palliative procedure were: multiple severe comorbidities in 28 cases; cognitive decline/dementia in 8 cases; cancer in 6 cases; frailty in 5 cases; multiple valve disease in 5 cases; patient refusal of TAVI in 3 cases; severe pulmonary hypertension in 1 case; cardiomyopathy in 1 case; and liver cirrhosis in 1 case. Among the 38 bridge to TAVI patients, 19 were finally excluded from definitive treatment for the following reasons:  excessive comorbidity in 7 patients; death before treatment in 1 patient; denied consent in 7 patients; and TAVI devices available not compatible with aortic annulus size in 4 patients. Of the 6 patients in the bridge to AVR group, 2 died before definitive treatment and 4 were finally excluded because of excessive comorbidity. The repeated BAV in our population was always clinically-driven in patients with persisting contraindication to definitive treatment, and discussions within the heart team and with the patient occurred when deemed appropriate because of relevant changes of clinical status. 

Echocardiographic data (Table 2) showed a high prevalence of tight degenerative aortic stenosis at baseline: average AVA was 0.63 ± 0.2 cm², with maximum TAG of 76 ± 25 mm Hg and mean TAG of 47 ± 17 mm Hg. Associated aortic regurgitation grade ≥ moderate was present in 20% of our population. Moderate pulmonary hypertension was present in nearly one-half of the patients at baseline. No systematic echocardiographic data were collected after the procedures.

As shown in Table 3, the average number of balloon dilations was 2.9 ± 0.9 and mean TAG decreased from 42 ± 18 mm Hg to 24 ± 9 mm Hg (see Supplemental Table 1A for detailed description of procedural data). In 60 cases (26.7%), a reduction ≥50% of the mean TAG was achieved. Percutaneous coronary intervention was performed concurrently with BAV in 20.5% of the procedures because of the detection of coronary artery disease (29.5% of patients at first BAV, 12.4% of patients at second BAV, 2% of patients at third BAV; no coronary interventions were performed between fourth and fifth BAV procedures). No intraprocedural deaths occurred. In-hospital events are reported in Table 4. Overall, vascular complications occurred in 8% of the 224 BAV procedures; major and minor vascular complications were observed in 4 procedures (1.8%) and 14 procedures (6.2%), respectively. Puncture-site hematoma occurred 11 times, while major access-site complications requiring surgical treatment recurred in 6 cases (2.7%). Life-threatening and major bleedings were observed in 6 patients (2.7%). Intraprocedural acute aortic regurgitation occurred in 6 cases out of 224 (2.7%); this complication was managed and resolved during the procedure in all cases.¹² Comparing the results of first and second BAV (same sample size), no differences in terms of myocardial infarction, stroke, or need for blood transfusion were documented and a decrease in terms of vascular complications (P<.001) and bleedings (P<.001) was shown in the second procedure (Supplemental Table 2A). Among the 11 patients who had a vascular complication during the first BAV, 3 patients had a vascular complication after the second procedure and 1 patient had a vascular complication after the third procedure. The logistic regression analysis for in-hospital events during the second BAV identified bleedings (odds ratio [OR], 6.88; 95% confidence interval [CI], 1.58-29.88; P=.01) and vascular complications (OR, 4.8; 95% CI, 1.19-19.31; P=.03) that occurred in the previous hospitalization to be strong independent predictors for the composite in-hospital endpoint of death, myocardial infarction, vascular complications, and bleedings. Mean time from first to second BAV was 409 ± 303 days; from second to third BAV was 301 ± 170 days, from third to fourth BAV was 252 ± 122 days, and the only fourth to fifth BAV was performed 373 days later. No changes in the local protocol for BAV were made between the first and subsequent procedures. However, a trend toward higher number of dilatations (3 [range, 1-5] vs 3 [range, 1-7]; P=.06) and lower efficacy was observed between the first and second procedures (mean TAG decrease, 23 ± 13 mm Hg vs 17 ± 11 mm Hg [P<.001]; mean AVA increase, 0.31 ± 0.18 cm² vs 0.26 ± 0.17 cm², respectively [P=.04]) (Supplemental Table 1A). Figure 2 illustrates the hemodynamic results of the first and second BAV procedures. Median follow-up after the first BAV was 785 days (range, 518-1286 days).

All-cause mortality at 1, 2, and 3 years was 15.2%, 41.3%, and 57.2%, respectively (Figure 3). The composite of death, myocardial infarction, and stroke occurred in 19%, 44.2%, and 60.1% at 1-year, 2-year, and 3-year follow-up, respectively. Hospital readmission for heart failure, including the repeat BAV procedure, was 40.7% at 1-year follow-up, 61.7% at 2-year follow-up, and 77.6% at 3-year follow-up.

Discussion

The present study was focused on feasibility and repeatability of BAV in elderly patients with severe symptomatic aortic stenosis who were not suitable for definitive treatment.

Survival rates at 1, 2, and 3 years (84.2%, 58.7%, and 42.8%, respectively) of our patient cohort who underwent ≥2 BAVs appear to be higher in comparison with untreated patients with aortic stenosis¹³ and with survival reported in other BAV registries. In one of the largest patient cohorts who underwent BAV during the 1990s, survival rates at 1, 2, and 3 years were 64%, 48%, and 37%, respectively.¹⁴ The Washington group¹⁵ reported a survival of 55% at 1 year, 35% at 2 years, and 23% at 3 years post BAV. The 1-year survival rate of successful BAV was 64% in the Mansfield registry, and 55% in the NHLBI registry.^4,16 Even in more recent reports, the prognosis of patients treated with stand-alone BAV was very poor, with 50% mortality at a median follow-up of 6 months in another paper from Washington¹⁷ and a survival <30% at 2 years and <20% at 3 years reported by Eltchaninoff et al¹⁸ in the medical treatment group (no bridge to definitive treatment). In our own experience, we also reported an overall mortality of 33% at 1 year and 54.4% at 2 years, rising to 44% and 67%, respectively, in patients who underwent BAV as a palliative treatment.¹⁹ Consistently, recent data from the PARTNER trial showed a dismal prognosis with stand-alone BAV; survival was 49.2% at 1 year, 32% at 2 years, and 19.1% at 3 years.²⁰ From this standpoint, the multiple-BAV strategy reported in the present study seems to be associated with a better clinical outcome. Notably, our patient outcomes are closer to the outcomes of the TAVI arm of the PARTNER Cohort B trial, with mortality rates of 41% at 2 years in our series vs 43% in PARTNER, and 57% vs 54% at 3 years, respectively.²⁰ Clearly, such an indirect comparison is limited by potential relevant differences in baseline characteristics and from a statistical standpoint should be considered meaningless. Nonetheless, our data generate the hypothesis that a repeat-BAV strategy might enhance the clinical benefit of stand-alone BAV and should be tested in dedicated prospective studies.

An important prerogative of any palliative treatment is safety. Our study confirms that, in recent years, BAV has become a relatively safe procedure. Periprocedural vascular complications have always been a critical issue in BAV. In previous series of patients who had multiple BAVs,²¹ vascular complication rates were reported to be as high as 13.5%. More recent data from Washington and Australian experiences^17,22 showed lower vascular complication rates (6.9% and 9%, respectively), which are similar to the 8% rate in the current study.¹¹ The experience of the centers, the less-invasive device profiles, and the use of vascular closure devices probably played a central role in this improved result. In our experience, in-hospital events did not increase from the first to the second BAV, with numerically lower rates of vascular complications, myocardial infarction, and bleedings (Supplemental Table 2A). However, patients who experienced a vascular complication during the first procedure appeared somehow at higher risk of repeated complications, possibly in relationship to individual risk factors, and deserve particular attention. Furthermore, the (low) incidence of acute aortic regurgitation and acute cerebrovascular events did not change between the first and subsequent procedures. These observations confirm the safety of multiple BAVs.

In our series, despite an average reduction of TAG and increase in AVA not significantly different from those reported by others, procedural success rate expressed by mean TAG reduction ≥50% was lower in comparison with other recent series.²³ As previously described,¹⁹ we do not use an aggressive approach in the attempt to achieve optimal results in terms of AVA and TAG reduction. Actually, many clinicians consider a reduction of 30%-50% in baseline TAG satisfactory and clinically relevant.²¹ Indeed, the prognostic implication of different parameters evaluated immediately after BAV is still unclear,¹⁷ with the possible exception of better clinical results when final AVA is >1 cm². Consistently, clinical outcomes associated with “efficacy” of the procedure (survival in primis) do not appear significantly different in our series in comparison with other single or multicenter experiences. These considerations led us to prefer a safer rather than a potentially more effective procedure. Recent data from a French registry challenge this approach, suggesting that a less aggressive procedure may be associated with a premature need for another procedure and with a notably reduced symptom-free period.¹⁸ Further studies are necessary to better evaluate technical aspects of BAV and to understand if a more aggressive approach should be recommended over a more conservative one. Another interesting observation is the apparent reduced hemodynamic efficacy of repeated procedures in our series (Supplemental Table 1A). This is evident, for example, from the higher number of dilatations and the lower reduction of TAG with the second versus the first BAV procedure. This finding requires further investigation.

Study limitations. The main limitation of this study is represented by its retrospective nature, which precludes direct comparison with patients who underwent a single BAV procedure in our registry and a reliable indirect comparison with results of other studies. Survival rate in our cohort may be artificially increased by a selection bias; in fact, our investigation selected all patients who underwent at least a second BAV, so necessarily included those who survived long enough after the first BAV to present with symptom recurrence. This bias is only partially mitigated by the observation that many patients with recurrent symptoms after BAV are not referred for a second procedure, or sometimes decline it because of the commonly perceived futility of BAV. On the other hand, a strategy of planned repeated BAV, for example based on tight clinical evaluations, might further increase clinical efficacy of repeated procedures. The study has been conducted at a single institution, and results may be different at other institutions using different BAV protocols or selecting different patient populations. Finally, no systematic echocardiographic evaluation was performed after the procedures or before hospital discharge, leading to incomplete information on procedural results.

Conclusion

BAV cannot be considered a definitive treatment of symptomatic aortic stenosis, and traditional AVR or TAVI must always be considered first and reconsidered at any time if the clinical status allows. When no other options are feasible, a strategy of repeated palliative BAV appears safe and might be associated with improved clinical outcomes.

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From the ¹Institute of Cardiology, Cardio-thoracic Department, University of Bologna, Policlinico S. Orsola-Malpighi, Bologna, Italy; and ²Regional Health Care Agency of Emilia-Romagna, Bologna, Italy.

Funding: This study was funded by the “Programma di ricerca Regione-Università – Regione Emilia Romagna 2010-2012 – Area 1 Innovative research. Title: Technological innovations in the treatment of heart failure. Scientific coordinator: Claudio Rapezzi.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted March 2, 2015, provisional acceptance given April 1, 2015, final version accepted May 19, 2015.

Address for correspondence: Francesco Saia, MD, PhD, Institute of Cardiology – University of Bologna Policlinico S. Orsola-Malpighi (Pad 21), Via Massarenti, 9, 40138 Bologna, Italy. Email: francescosaia@hotmail.com