An analysis of long-term clinical outcome following the use of excimer laser coronary atherectomy in a large UK PCI center.

BACKGROUND: Excimer laser atherectomy (ELCA) is an established adjunctive technique to facilitate acute success in percutaneous coronary intervention (PCI). Despite this there are a lack of contemporary outcome data, particulary longer-term, forpatients treated with ELCA PCI. AIMS: To evaluate the contemporary use ofELCA in PCI, the frequency of periprocedural complications and the longer-term outcomes associated with ELCA PCI. METHODS: This was a retrospective study that included all patients undergoing PCI (with or without ELCA) between April 2005 and May 2021. Relevant features from all cases were downloaded from the patient record and matched to hospital data on mortality on November 22, 2022. Kaplan Meier curves were used to compare mortality between the ELCA PCI and non-ELCA PCI cohorts with a landmark at 1 year. Multivariable Cox regression was performed to assess whether ELCA PCI was independently associated with long-term mortality. RESULT: There were 21,256 patients in this analysis, of which 448 (2.1%) were treated with ELCA PCI. ELCA PCI was associated with a higher frequency of any periprocedural complication. Median follow-up was 2812 days (IQR, 1577-4245 days) with higher mortality in ELCA PCI (38.2% vs. 29.0%, p < 0.001). However, on multivariable analysis, ELCA PCI was not independently associated with long-term mortality. The TVR frequency in ELCA PCI was 16.7% but TVR was significantly higher for cases of in-stent restenosis (ISR) (29.5%). CONCLUSION: Despite ELCA PCI being used in higher risk populations with complex coronary artery disease there was no long-term increased mortality associated with the use of this device. ELCA PCI for ISR is highly effective and safe although TVR in this cohort remains high in long-term follow-up.

Novel application of intravascular lithotripsy in stent under-expansion: A single-center experience.

INTRODUCTION: Stent under-expansion due to calcification is associated with a less durable result. The development of intravascular lithotripsy (IVL) has provided clinicians with a readily available, simple-to-use treatment option for coronary calcification, but the use of IVL within a previously stented segment is currently off-license. There are, however, developing data suggesting that the use of IVL can be an effective treatment option for patients with calcific stent under-expansion. METHOD: This was a single-center study of all patients treated with IVL for calcific stent under-expansion between January 2019 and June 2021. The impact of IVL on quantitative coronary angiography (QCA) stenosis and on the minimal stent area (MSA) derived from intracoronary imaging were recorded. The presence of periprocedural complications and adverse cardiovascular events was obtained from the clinical record during the study timeframe. RESULTS: Thirty-nine patients underwent IVL for calcific stent under-expansion during the study time frame with one patient treated with more than one lesion in the same session. In all lesions, there was an improvement in the QCA stenosis with 37 (92.5%) having a residual stenosis of ≤30%. The mean QCA stenosis pre-IVL was 68 ± 21% and following IVL the mean QCA was 18 ± 9% (p < 0.001). In all lesions, there was an improvement in the MSA, with 26 (92.9%) achieving an MSA of more than 4.5 mm2 . The mean MSA pre-IVL was 3.88 ± 1.51 mm2 and following IVL the mean MSA was 7.41 ± 2.34 mm2 (p < 0.001). There were no major procedural complications. Over a mean follow-up of 506 ± 277 days, one patient died from ventricular arrhythmia but there were no other major adverse cardiovascular events. CONCLUSION: This single-center study demonstrates that IVL is a safe and effective treatment for calcific stent under-expansion with good medium-term results.

Rotablation in the Very Elderly - Safer than We Think?

BACKGROUND/PURPOSE: Calcified coronary artery stenosis remains a challenge for Percutaneous Coronary Intervention (PCI). Calcium modification is facilitated by rotablation and is used in 1-3% of cases. Data on rotablation in patients ≥80 years is limited and perceived to be high risk. We compared PCI with rotablation and outcomes between patients ≥80 years and those <80 years. METHODS/MATERIALS: Retrospective analysis was performed of consecutive patients who underwent rotablation and PCI from 3 United Kingdom (UK) PCI Centres (2014-2017). In-hospital outcomes (composite of stroke, myocardial infarction, death, emergency coronary artery bypass graft surgery, vascular damage, coronary perforation, advanced AV-block, bleeding and renal impairment) and 30 day mortality risk score was compared between groups. RESULTS: 213 patients were included. 33.3% (n = 71) were ≥80 years. Baseline and angiographic characteristics were similar in the two groups. Older patients were more likely to present with acute coronary syndrome (ACS) (≥80 years 53.5% vs. 33.8% in <80 years, p = 0.006) and had increased hospital stay (≥80 years 2.8 days (±6.0) vs. 1.3 days (±1.9) <80 years, p = 0.009). Majority of PCI were performed through radial access (≥80 years 91.5% vs. 88.0% <80 years, p = 0.43). In-hospital composite outcomes were similar between the groups (≥80 years 5.6% vs. 4.9% <80 years, p = 1.0). The 30-day mortality risk score demonstrated a higher average risk of 2.5% in ≥80 years versus under 1% risk in <80 years (p < 0.001). CONCLUSION: This study demonstrates that outcomes after rotablation in the very elderly are similar to younger patients despite being high risk and presenting with ACS.

Effects of Intracoronary Alteplase on Microvascular Function in Acute Myocardial Infarction.

Background Impaired microcirculatory reperfusion worsens prognosis following acute ST-segment-elevation myocardial infarction. In the T-TIME (A Trial of Low-Dose Adjunctive Alteplase During Primary PCI) trial, microvascular obstruction on cardiovascular magnetic resonance imaging did not differ with adjunctive, low-dose, intracoronary alteplase (10 or 20 mg) versus placebo during primary percutaneous coronary intervention. We evaluated the effects of intracoronary alteplase, during primary percutaneous coronary intervention, on the index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio. Methods and Results A prespecified physiology substudy of the T-TIME trial. From 2016 to 2017, patients with ST-segment-elevation myocardial infarction ≤6 hours from symptom onset were randomized in a double-blind study to receive alteplase 20 mg, alteplase 10 mg, or placebo infused into the culprit artery postreperfusion, but prestenting. Index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio were measured after percutaneous coronary intervention. Cardiovascular magnetic resonance was performed at 2 to 7 days and 3 months. Analyses in relation to ischemic time (<2, 2-4, and ≥4 hours) were prespecified. One hundred forty-four patients (mean age, 59±11 years; 80% male) were prospectively enrolled, representing 33% of the overall population (n=440). Overall, index of microcirculatory resistance (median, 29.5; interquartile range, 17.0-55.0), coronary flow reserve(1.4 [1.1-2.0]), and resistive reserve ratio (1.7 [1.3-2.3]) at the end of percutaneous coronary intervention did not differ between treatment groups. Interactions were observed between ischemic time and alteplase for coronary flow reserve (P=0.013), resistive reserve ratio (P=0.026), and microvascular obstruction (P=0.022), but not index of microcirculatory resistance. Conclusions In ST-segment-elevation myocardial infarction with ischemic time ≤6 hours, there was overall no difference in microvascular function with alteplase versus placebo. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02257294.

Towards Low Energy Atrial Defibrillation.

A wireless powered implantable atrial defibrillator consisting of a battery driven hand-held radio frequency (RF) power transmitter (ex vivo) and a passive (battery free) implantable power receiver (in vivo) that enables measurement of the intracardiac impedance (ICI) during internal atrial defibrillation is reported. The architecture is designed to operate in two modes: Cardiac sense mode (power-up, measure the impedance of the cardiac substrate and communicate data to the ex vivo power transmitter) and cardiac shock mode (delivery of a synchronised very low tilt rectilinear electrical shock waveform). An initial prototype was implemented and tested. In low-power (sense) mode, >5 W was delivered across a 2.5 cm air-skin gap to facilitate measurement of the impedance of the cardiac substrate. In high-power (shock) mode, >180 W (delivered as a 12 ms monophasic very-low-tilt-rectilinear (M-VLTR) or as a 12 ms biphasic very-low-tilt-rectilinear (B-VLTR) chronosymmetric (6ms/6ms) amplitude asymmetric (negative phase at 50% magnitude) shock was reliably and repeatedly delivered across the same interface; with >47% DC-to-DC (direct current to direct current) power transfer efficiency at a switching frequency of 185 kHz achieved. In an initial trial of the RF architecture developed, 30 patients with AF were randomised to therapy with an RF generated M-VLTR or B-VLTR shock using a step-up voltage protocol (50-300 V). Mean energy for successful cardioversion was 8.51 J ± 3.16 J. Subsequent analysis revealed that all patients who cardioverted exhibited a significant decrease in ICI between the first and third shocks (5.00 Ω (SD(σ) = 1.62 Ω), p < 0.01) while spectral analysis across frequency also revealed a significant variation in the impedance-amplitude-spectrum-area (IAMSA) within the same patient group (|∆(IAMSAS1-IAMSAS3)[1 Hz - 20 kHz] = 20.82 Ω-Hz (SD(σ) = 10.77 Ω-Hz), p < 0.01); both trends being absent in all patients that failed to cardiovert. Efficient transcutaneous power transfer and sensing of ICI during cardioversion are evidenced as key to the advancement of low-energy atrial defibrillation.

Fluoroscopic and electrical assessment of implantable cardioverter defibrillator leads: a prospective observational study.

BACKGROUND: Insulation defects resulting in conductor externalization (CE) have been reported in the Riata family of implantable cardioverter defibrillator (ICD) leads (St. Jude Medical, Sylmar, CA, USA). The aim of this study was to identify, prospectively, the rate of CE and outcomes following this, within a group of patients with a Riata ICD lead. METHODS: Patients with a Riata ICD lead attended for fluoroscopic screening and electrical assessment of the lead at yearly intervals between 2010 and 2012. RESULTS: One hundred and forty patients had no or borderline evidence of CE on initial assessment in 2010. These patients were prospectively followed for 3 years (304.6 patient-years). During this time, 11 patients developed definite CE, equating to an event rate of 3.6 (95% confidence intervals: 1.8-6.5) per 100 patient-years of follow-up. Of those patients developing definite CE, one patient had the ICD lead explanted (for reasons unrelated to CE) and no patients died. CE was not associated with any electrical abnormalities of the ICD lead. CONCLUSIONS: CE was observed at a rate of 3.6 per 100 patient-years of follow-up, in 140 individuals with a Riata ICD lead and no definite evidence of CE at baseline.

Fluoroscopic and electrical assessment of a series of defibrillation leads: prevalence of externalized conductors.

INTRODUCTION: Insulation defects with externalized conductors have been reported in the St. Jude Riata(®) family of defibrillation leads (St. Jude Medical, Sylmar, CA, USA). The objective of the Northern Ireland Riata(®) lead screening program was to identify insulation defects and externalized conductors by systematic fluoroscopic and electrical assessment in a prospectively defined cohort of patients. We sought to estimate the prevalence, identify risk factors, and determine the natural history of this abnormality. METHODS: All patients with a Riata(®) lead under follow-up at the Royal Victoria Hospital were invited for fluoroscopic imaging and implantable cardioverter-defibrillator lead parameter checks. Fluoroscopic images were read independently by two cardiologists and the presence of externalized conductors was classified as positive, negative, or borderline. RESULTS: One hundred and sixty-five of 212 patients with a Riata lead were evaluated by fluoroscopy and lead parameter measurements. The mean duration after implantation was 3.98+/-1.43 years. After screening 25 (15%) patients were classified as positive, 137 (83%) negative, and three (1.8%) borderline. Time since implantation (P = 0.001), presence of a single coil lead (P = 0.042), and patient age (P = 0.034) were significantly associated with externalized conductors. The observed rate of externalized conductors was 26.9% for 8-French and 4.7% for 7-French leads. No leads that were identified prospectively with externalized conductors had electrical abnormalities. Seven of 25 (28%) patients had a defective lead extracted by the end of this screening period. CONCLUSION: A significant proportion (15%) of patients with a Riata lead had an insulation breach 4 years after implantation. High-resolution fluoroscopic imaging in at least two orthogonal views is required to identify this abnormality.

Short-term efficacy of palliative balloon aortic valvuloplasty in selected patients with high operative risk.

UNLABELLED: With the introduction of transcatheter aortic valve implantation (TAVI), the precise role of balloon aortic valvuloplasty (BAV) remains to be established. METHODS: Between August 2008 and November 2010, consecutive patients undergoing BAV for severe aortic stenosis (AS) in our center were enrolled. The primary endpoint was survival to hospital discharge. Secondary endpoints were 30-day survival and progression to aortic valve replacement (AVR). RESULTS: Enrolled were 64 patients (age, 82 ± 8 years; 45% male). Treatment objectives were: symptom palliation (69%); potential AVR (23%); and facilitation of withdrawal of ventilation or non-cardiac surgery (8%). At baseline, patients had logistic EuroSCORE of 35.7 ± 19.5, NT-proBNP of 11,195 ± 11,694 ng/L, aortic valve area of 0.53 ± 0.17 cm², and peak transaortic gradient (PG) of 75.2 ± 25.3 mm Hg. The primary endpoint of survival to hospital discharge was reached by 97% patients. The secondary endpoint of 30-day mortality occurred in 8 patients (13%). Overall, 12 patients showed clinical improvement within 1 month of BAV. Of these, 8 patients underwent AVR (TAVI in 3/8 [38%]). After multivariate adjustment, the strongest correlates for 30-day survival and progression to AVR pre-BAV were: New York Heart Association ≤II, SBP ≥90 mm Hg, estimated glomular filtration rate ≥45 mL min-1, left ventricular ejection fraction ≥45% and transaortic PG <80 mm Hg. CONCLUSION: In patients with severe AS and high operative risk, BAV has the potential to facilitate progression to TAVI in those who are technically suitable.

Waveform optimization for internal cardioversion of atrial fibrillation.

INTRODUCTION: A novel atrial defibrillator was developed at the Royal Victoria Hospital in collaboration with the Nanotechnology and Integrated Bio-Engineering Centre, University of Ulster. This device is powered by an external pulse of radiofrequency energy and designed to cardiovert using low-tilt monophasic waveform (LTMW) and low-tilt biphasic waveform (LTBW), 12 milliseconds pulse width. This study compared the safety and efficacy of LTMW with LTBW for transvenous cardioversion of atrial fibrillation (AF). METHODS: Patients were anticoagulated with warfarin to maintain International Normalized Ratio between 2 and 3 for 4 weeks prior cardioversion. Warfarin international normalized ratio level was maintained in between 2 and 3 for 4 weeks prior cardioversion. St Jude's defibrillating catheter was positioned in the distal coronary sinus and right atrium and connected to the defibrillator via a junction box. After a test shock using a dummy load, the patient was cardioverted in a step-up progression from 50 to 300 V. Shock success was defined as return of sinus rhythm for 30 seconds or more. If cardioversion was unsuccessful at peak voltage, the patient was crossed over to the other arm of the waveform type and cardioverted at peak voltage. RESULTS: Thirty patients were randomized equally to LTBW and LTMW (15 each). Seven out of 15 patients (46%) cardioverted to sinus rhythm with LTBW, and 1 (6%) of 15, with LTMW (P = .035). Including crossover patients, 14 patients (46%) converted to sinus rhythm. After crossover, 4 patients were cardioverted with LTBW and 2 with LTMW. Overall mean voltage, current, and energy used for cardioversion were 270.53 ± 35.96 V, 3.68 ± 0.80 A, and 9.12 ± 3.73 J, respectively, and intracardiac impedance was 70.82 ± 13.46 Ω. For patients who were successfully cardioverted, mean voltage, current, energy, and intracardiac impedance were 268.28 ± 42.41 V, 3.52 ± 0.63 A, 8.51 ± 3.16 J, and 73.92 ± 12.01 Ω. There were no major adverse complications during the study. Cardiac markers measured postcardioversion were unremarkable. CONCLUSION: Low-tilt biphasic waveform was more efficacious for low-energy transvenous cardioversion of AF. A significant proportion of patients were successfully cardioverted to sinus rhythm with low energy. Radiofrequency-powered defibrillation can be safely used for transvenous cardioversion of AF.