Mattia Lunardi

Clinical outcomes of transcatheter aortic valve implantation: from learning curve to proficiency

Objective The use of transcatheter aortic valve implantation (TAVI) is growing rapidly in countries with a predominantly elderly population, posing a huge challenge to healthcare systems worldwide. The increment of human and economic resource consumption imposes a careful monitoring of clinical outcomes and cost-benefit balance, and this article is aimed at analysing clinical outcomes related to the TAVI learning curve. Methods Outcomes of 177 consecutive transfemoral TAVI procedures performed in 5 years by a single team were analysed by the Cumulative Sum of failures method (CUSUM) according to the clinical events comprised in the Valve Academic Research Consortium (VARC-2) safety end point and the VARC-2 definition of device success. Margins for events acceptance were extrapolated from landmark trials that tested both balloon or self-expandable percutaneous valves. Results 30-day and 1-year survival rates were 97.2% and 89.9%, respectively. Achievement of the primary end point (number of cases needed to provide the acceptable margin of the composite end point of any death, stroke, myocardial infarction, life-threatening bleeding, major vascular complications, stage 2–3 acute kidney injury and valve-related dysfunction requiring a repeat procedure) required the performance of 54 cases, while the learning curve to achieve ‘device success’ identified 32 cases to reach the expected proficiency. In this experience, the baseline clinical risk as assessed by the Society of Thoracic Surgeons (STS) score determined the long-term survival rather than the adverse events related to the learning curve. Conclusions A relatively large number of cases are required to achieve clinical outcomes comparable to those reported in high-volume centres and controlled trials. According to our national workload standards, this represents more than 2 years of continuous activity.

Coronary Catheterization and Percutaneous Interventions After Transcatheter Aortic Valve Implantation

Coronary artery disease (CAD) is often present in patients with severe aortic valve stenosis candidates to transcatheter aortic valve implantation (TAVI). Mild CAD may also worsen and need treatment years after TAVI. The implantation of a transcatheter valve may interfere with the capability of reengaging the coronary arteries. We prospectively assessed the feasibility of performing coronary angiography (CA), fractional flow reserve, and, where indicated, percutaneous coronary intervention after valve implantation in a consecutive series of patients with CAD undergoing TAVI. Valve type and size were decided according to accurate computed tomography scan and angiographic measurement of the aortic root structures. We analyzed 66 consecutive patients undergoing TAVI, 41 with balloon-expandable, and 25 with self-expandable transcatheter valves. Right and left coronary catheterization (132 vessels) was successful in all cases except in 1 left coronary artery after a high implantation of a self-expandable valve (unsuccess rate, 1 in 50 vessels). In 6 of 132 vessels (4%), CA was initially nonselective, but after positioning the 0.014″ intracoronary guidewire, selective injections were obtained in all these cases. Percutaneous coronary intervention was performed successfully in 19 coronary vessels (17 patients) as indicated by fractional flow reserve measurements. In conclusion, catheterization of the coronary ostia after transfemoral TAVI with balloon or self-expandable valves is safe and feasible in almost all cases. Accurate imaging of the aortic root and procedural planning may help to avoid too high implantation of supra-annular self-expandable valves to obviate difficulties in accessing coronary ostia. Use of intracoronary guidewires facilitates selective CA in cases with difficult access.

Physiologic evaluation of coronary lesions using instantaneous wave-free ratio (iFR) in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation

AIMS We sought to assess eventual changes in iFR measurements in patients with aortic stenosis (AS) before and after TAVI in coronary lesions with different degrees of angiographic severity. METHODS AND RESULTS The functional relevance of 145 coronary lesions was assessed by online iFR and FFR measurement in 66 patients with severe AS before and after TAVI, during the same procedure. The iFR-FFR classification agreement was calculated for pre-TAVI and post-TAVI measurements. Mean iFR values remained identical before and after TAVI, irrespective of the angiographic severity of the coronary stenosis (0.89±0.12 vs. 0.89±0.12, p=0.66). However, individual iFR values varied widely after TAVI and the 0.89 iFR threshold was crossed by 15% of the investigated coronary lesions. Higher iFR variation was related to a higher transaortic gradient drop after valve intervention. The diagnostic accuracy of iFR in predicting an FFR ≤0.8 was poor (65%) in lesions with severe obstructions, and tended to increase post TAVI. CONCLUSIONS Although overall values did not change after TAVI, iFR presented significant and mostly erratic individual variations after valve replacement. Delta iFR was influenced by the extent of the transaortic gradient drop induced by TAVI. Therefore, caution is advisable in the interpretation of iFR in the presence of AS.

Coronary physiology in patients with severe aortic stenosis: Comparison between fractional flow reserve and instantaneous wave-free ratio

BACKGROUND The functional assessment of coronary artery disease (CAD) in patients with aortic stenosis (AS) has not been validated so far, and the best strategy to physiologically investigate the relevance of coronary stenosis in this specific setting of patients remains undetermined. The aim of the study is to compare the diagnostic performance of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with severe AS. METHODS The functional significance of 179 coronary lesions was investigated with on-line iFR and FFR measurements in 85 AS patients and compared with a control group formed by 167 patients (290 lesions) with stable CAD and without AS. The iFR-FFR diagnostic agreement has been tested using the conventional 0.80 FFR cut-off. RESULTS The correlation between iFR and FFR was similar between AS and CAD patients, as well as the area under the curve at ROC curve analysis (0.97 vs 0.96, p=0.88). However, using the standard iFR 0.89 threshold, the diagnostic accuracy of iFR was significantly lower in AS compared with CAD (76.3% vs 86.1%, p=0.009). According to ROC analysis, the best iFR cut-off in predicting FFR≤0.8 was lower in AS (0.83, J=0.82) compared with CAD (0.89, J=0.81). Using the ROC derived cut-off of 0.83, the iFR accuracy increased significantly (91.3%, p=0.003) while maintaining an elevated negative predictive value (95.5%). CONCLUSIONS In the presence of severe AS, conventional iFR cut-off had lower diagnostic agreement with FFR classification of coronary lesions compared to stable CAD patients. AS seems to influence iFR cut-off ischemic thresholds and deserves further comparative studies.

Expanding TAVI options: elective rotational atherectomy during trans-catheter aortic valve implantation.

Aortic valve stenosis (AVS) in the elderly is frequently associated to coronary artery disease (CAD). In patients with significant coronary stenosis surgical valve replacement is associated to coronary bypass grafting, but whether coronary angioplasty is needed in patients receiving trans-catheter aortic valve implantation (TAVI) is unknown. Given the frequent complexity of CAD in the elderly with calcific AVS, rotational atherectomy (RA) may be needed in some cases. No data are available about feasibility and safety of RA during TAVI. The need for myocardial revascularization in TAVI candidates is discussed, and a series of RA cases performed during TAVI is described.

Drug-coated balloon: Long-term outcome from a real world three-center experience.

OBJECTIVES In-stent restenosis (ISR) and diffuse small vessel disease still represent challenging subsets for percutaneous coronary interventions, also in the new-generation DES era. We aim at reporting on the long-term clinical outcome of drug-coated balloons (DCB) in all-comers population. METHODS Consecutive patients treated with DCB between January 2011 and December 2014 were retrospectively studied in three centers of northern Italy. The measured end-points were cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), and major adverse cardiac events (MACE) defined as combination of cardiac death, MI, and TLR. RESULTS We included 143 patients. Of the 167 lesions treated, 41 (24.5%) were de novo lesions in small coronary vessels (<2.5 mm) and 126 (75.4%) were ISR. Among ISR lesions, 78.5% were DES-ISR, 32.5% were focal, 15.8% multifocal, 30.1% diffuse, 18.2% proliferative, and 3.1% were total occlusions. Procedural success was achieved in 94.6% of cases. Overall survival free from MACEs was 91.6% at 12 months, and 75.3% at 48 months, with a total of 3 cardiac deaths, 8 MI, and 27 TLR. No thrombotic event occurred in the treated segments. There were no differences in MACESs between the ISR and de novo lesions groups. At multivariate analysis, acute coronary syndromes, previous MI, previous surgical revascularization, peripheral arterial disease and diabetes were independent predictors of MACEs at long-term follow-up. CONCLUSIONS DCB proved a valid revascularization strategy in an all-comers population of patients with ISR and de novo lesions in small vessels, with an acceptable rate of cardiac events up to 48 months follow-up.

Drug eluting balloon for the treatment of patients with coronary artery disease: Current perspectives

Despite the improvement of outcomes after the introduction of bare metal and drug eluting stents for the treatment of CAD, certain type of patients have still an increased risk of stent failure. An alternative is represented by drug-eluting balloons (DEB). This innovation could give potential benefits in particular for the in-stent restenosis (ISR) and the de-novo lesions. In the first setting DEB have shown results superior to those with plain-balloon angioplasty and similar to those with first generation DES. Their performance seems to be more evident in BMS-ISR than in DES-ISR, showing a reliable effectiveness in those cases of recalcitrant ISR or when dual antiplatelet therapy is not indicated. In the context of de-novo lesions the use of DEB as unique strategy results more safe and feasible than a strategy with combined BMS implantation. The results are comparable to DES in lesions limited to small coronary vessels. Other particular scenarios, like bifurcations, acute myocardial infarction and diffuse disease, have been approached with DEB resulting in very heterogeneous outcomes. At present, given the high efficacy of last generation DESs, DEBs should be considered where clinical and angiographic conditions require the avoidance of stent implantation.

Long-term follow-up after trans-catheter tricuspid valve-in-valve replacement with balloon–expandable aortic valves

BACKGROUND Transcatheter tricuspid VIV replacement has been proposed as a feasible option for high-risk patients with previous tricuspid valve replacement that undergo valve degeneration causing refractory heart failure. However, little is known about the long-term outcome of patients treated with transcatheter tricuspid VIV. We evaluate the safety of transcatheter tricuspid valve-in-valve (VIV) replacement by using balloon-expandable aortic valve stents and the long-term follow-up. METHODS AND RESULTS From January 2013 to March 2016, 4 patients underwent transcatheter tricuspid VIV in our center using balloon-expandable Edwards Sapien-XT and Sapien-3 valves. In all cases the procedure succeeded with significant improvement of the tricuspid valve area (from 0.98±0.29cm2 to 3.1±0.45cm2, p=0.005), right atrial pressure (from 21±7.78mmHg to 8.5±2.51mmHg, p=0.025) and mean trans-valvular gradient (from 11.5±4mmHg to 3.32±1.28mmHg, p=0.02). Three out of 4 patients presented a follow up longer than 2.5years. At median follow up of 32months (range 9-47months) all patients were alive and presented with NYHA class I-II. Only one patient, who presented impaired right ventricular function at baseline, experienced re-hospitalization during the follow-up time. Echocardiographic assessment at long-term disclosed a well-maintained hemodynamic performance with low trans-valvular gradients and no significant valvular regurgitation in all cases. CONCLUSIONS In our experience, trans-catheter tricuspid VIV demonstrated good long-term results in terms of valve performance and functional class improvement at 32months from intervention.

Effectiveness and Safety of Transcatheter Aortic Valve Implantation in Patients With Pure Aortic Regurgitation and Advanced Heart Failure

Results of transcatheter aortic valve implantation (TAVI) for treatment of severe noncalcific isolated aortic regurgitation (AR) complicated by advanced heart failure or cardiogenic shock has been previously reported only in isolated case reports. Current self-expanding transcatheter aortic valves are designed to treat aortic valve stenosis, and have also been implanted in cases of severe AR due to degenerated bioprosthesis and in very few cases of native aortic valves. We report 13 consecutive inoperable patients with noncalcific, pure AR, and advanced heart failure treated with emergency percutaneous transfemoral implantation with self-expandable CoreValves at our institution between July 2012 and September 2017. The immediate and long-term clinical outcome was prospectively assessed according to the Valve Academic Research Consortium-2 criteria for device success and safety. All but 3 patients had previous surgery of the aortic root, including 2 implants of Heart Mate-II left ventricle assist device; none had surgical aortic bioprosthesis at the time of the TAVI. Valve implantation was successful in 12 of 13 patients (92%) and 1 patient required a second unplanned valve procedure within 18 hours. Oversizing the prosthesis by approximately 15% yielded better results with 1 valve. Two patients with left ventricle assist device died within 30 days of TAVI. All patients who survived to hospital discharge had none or just mild residual AR, improved their cardiac function, and survived at long-term without recurrence of clinical events. In conclusion, implanting self-expandable transcatheter valves in patients pure AR in this small study was safe and effective, and represented an important option for inoperable patients with noncalcific severe AR.