Balloon aortic valvuloplasty – still an option?
Balloon aortic valvuloplasty (BAV) remains an option for temporary
palliation and symptomatic relief in such patients. However, long-term
survival after BAV alone remains poor, with a high occurrence of
valvular restenosis[5]. BAV can also play an important role as a
bridge to either surgical or TAVR in patients with AS requiring
temporary haemodynamic stabilization. However, there may be significant
delays between BAV and AVR or TAVR[6]. In a multicenter registry of
811 patients with severe AS who underwent BAV, at a median follow-up of
318 days, only 30.9% of patients undergoing BAV as a bridge to TAVR and
15.8% of patients undergoing BAV as a bridge to SAVR actually underwent
AVR[7]. Additionally in this study, 56.5% of patients who underwent
urgent/emergent TAVR had a prior history of BAV, suggesting that BAV may
not be effective in preventing subsequent acute decompensation and need
for urgent/emergent TAVR.
Ali et al. [8] compared strategies in the treatment of decompensated
severe aortic stenosis. The authors hypothesised that undertaking urgent
or emergency TAVR directly in such patients is safer and more effective
than urgent or emergency balloon aortic valvuloplasty (BAV) followed by
elective TAVR or surgical aortic valve replacement (SAVR). Between
September 2014 and February 2018, 52 patients underwent urgent or
emergency BAV and 87 underwent TAVR. Significant differences were noted
between the two groups in 30-day all-cause mortality (88.5% BAV
patients alive at 30 days, 97.7% TAVR patients) and 1-year all-cause
mortality (44.2% BAV patients alive at 1 year, 88.5% TAVR patients).
Patients in the BAV group who successfully underwent subsequent TAVR or
SAVR all survived for 365 days, but there was no significant 1-year
mortality difference compared with those who underwent urgent or
emergency TAVR (100 vs. 88.5%; P > 0.155). These results
suggest treatment of decompensated severe aortic stenosis with urgent or
emergency TAVR may be associated with improved survival outcomes when
compared with a strategy of performing BAV as a bridge to subsequent
TAVR or SAVR.
Kolte et al.[9] examined outcomes and identified independent
predictors of mortality among patients undergoing urgent/emergent TAVR.
The Society of Thoracic Surgeons and the American College of Cardiology
Transcatheter Valve Therapy (STS/ACC TVT) Registry linked with Centers
for Medicare & Medicaid Services claims was used to identify patients
who underwent urgent/emergent versus elective TAVR between November 2011
and June 2016. Of 40,042 patients who underwent TAVR, 3,952 (9.9%) were
urgent/emergent. Device success rate was statistically lower, after
urgent/emergent versus elective TAVR (92.6% vs. 93.7%). Rates of major
and/or life-threatening bleeding, major vascular complications,
myocardial infarction, stroke, new permanent pacemaker placement,
conversion to SAVR, and paravalvular regurgitation were similar between
the 2 groups. Compared with elective TAVR, patients undergoing
urgent/emergent TAVR had higher rates of acute kidney injury (AKI)
and/or new dialysis (8.2% vs. 4.2%), 30-day mortality (8.7% vs.
4.3%,), and 1-year mortality (29.1% vs. 17.5%). The authors conclude
that urgent/emergent TAVR is feasible with acceptable outcomes
and may be a reasonable option in a selected group of patients with
severe AS.
AKI and new dialysis are more common following urgent/emergent versus
elective TAVR. The causes of AKI after TAVR are many including
hypotension/hypoperfusion during rapid pacing, contrast-induced AKI
(CIAKI), bleeding and blood transfusions. Pre-procedure renal
dysfunction, diabetes, impaired left ventricular function, are also more
common in patients undergoing urgent/emergent TAVR and are associated
with an increased risk of new dialysis after TAVR[11] Furthermore,
patients requiring urgent/emergent TAVR may undergo pre-operative CT
scans and cardiac catheterization within a short period of time,
increasing the risk of CIAKI. However, after adjusting for baseline
patient and procedural characteristics, Ferro et al. [11]found no
significant difference in the adjusted odds of AKI/new dialysis between
urgent/emergent vs elective TAVR, suggesting that the observed
differences in the rates are related to differences in baseline clinical
risk profile rather than the procedure itself. Use of 3-dimensional
transoesophageal echocardiography and non-contrast imaging for
pre-procedural AV annulus assessment may help decrease the risk of
CIAKI/new dialysis in patients at increased risk of this complication,
including those undergoing urgent/emergent TAVR[12-14].
In patients undergoing urgent/emergent TAVR, oxygen-dependent lung
disease, immunocompromised status, pre-existing atrial
fibrillation/flutter, higher baseline creatinine, concomitant mitral
stenosis, non-femoral access, are associated with an increased risk of
1-year mortality. Several of these variables have also been shown to
predict poor outcome following TAVR[15-16]. Thus, TAVR, especially
as an urgent/emergent procedure, might be considered medically futile in
patients with 1 or more of these comorbidities and such patients should
be considered for emergency BAV as a palliative therapy or bridge to
decision.