Catheter-Induced Postextrasystolic Potentiation in the Assessment of Severity of Low-Gradient Aortic Valve Stenosis.

BACKGROUND: Deciphering which patients with low-gradient aortic valve disease have severe stenosis can be difficult. We aimed to correlate the postextrasystolic potentiation (PESP) with dobutamine stress echocardiography and multidetector computed tomography in patients with low-gradient aortic valve stenosis. METHODS: Patients with an aortic valve area ≤1 cm2 and a mean gradient <40 mm Hg were included. Aortic valve stenosis severity was assessed by a core lab with dobutamine stress echocardiography, followed by a multidetector computed tomography aortic valve score if indeterminate. A premature ventricular contraction was induced by intentional catheter contact with the myocardium within the left ventricle. PESP was calculated as a percent change of pre-to-post mean gradient. Multidetector computed tomography was used to measure the aortic valve calcification score, and subsequently, aortic valve calcification density. RESULTS: Twenty-eight patients (age, 77±10 years; 19 female) were included. Dobutamine stress echocardiography increased mean gradient from baseline of 25±7 mm Hg to 36±11 mm Hg; pre-premature ventricular contraction mean gradient was 25±7 mm Hg and increased to post-premature ventricular contraction mean gradient of 32±10 mm Hg, representing a PESP of 24±11%. A ≥20% in PESP resulted in 100% sensitivity, 77% specificity, 83% positive predictive value, and 100% negative predictive value for diagnosing severe aortic valve stenosis. There was a significant correlation between PESP and projected aortic valve area and aortic valve calcification density (R=-0.64, P=0.0003; R=0.057, P=0.014, respectively). CONCLUSIONS: In patients with low-gradient aortic valve stenosis, catheter-induced premature ventricular contractions during cardiac catheterization causing ≥20% PESP has a 100% sensitivity for severe aortic valve stenosis. Validation of this 20% cutoff in larger groups with correlation to clinical end points is required.

Can ED chest pain patients with intermediate HEART scores be managed as outpatients?

PURPOSE: Current guidelines recommend hospital admission for patients who present to the emergency department (ED) with chest pain and are scored as intermediate risk for adverse outcomes based on the HEART score. While hospital admission for these patients allows for timely investigation and treatment, it is a resource-intensive process. This study examines whether intermediate HEART score patients can be safely managed on an outpatient basis through rapid access chest pain clinics. METHODS: This retrospective observational study included all ED chest pain patients referred to rapid access clinics from January 2018 to April 2020 in Regina and Saskatoon, Saskatchewan. ED physician HEART scores were used in lieu of reviewer HEART scores when available. The primary outcome was the rate of major adverse coronary events (MACE), a composite measure of death, acute coronary syndrome, stroke, coronary angiography, and revascularization at 6 weeks in intermediate-risk patients. Secondary outcomes were the type of MACE, rate of MACE before rapid access clinic appointment and the most predictive component of the HEART score. RESULTS: There were 1989 ED referrals, of which 817 were for intermediate-risk patients. 9.3% of intermediate-risk patients had a MACE at 6 weeks. MACE occurred before rapid access clinic follow-up in 1.1% of intermediate-risk patients, with coronary angiography being the most common MACE. Excluding coronary angiography, the risk of MACE before rapid access clinic follow-up was 0.7% in intermediate-risk patients. Components of the HEART score most predictive of MACE were troponin (OR 11.0, 95% CI: 3.7-32.3) and history (5.3, 95% CI: 2.4-11.8). CONCLUSION: This study demonstrates that rapid access clinics are likely a safe alternative to admission for intermediate-risk chest pain patients and could reduce costly inpatient admissions for chest pain. With angiography excluded, MACE rates were well below the American College of Emergency Physicians cited 2% threshold.

RéSUMé: OBJECTIF: Les directives actuelles recommandent l'admission à l'hôpital des patients qui se présentent aux urgences avec une douleur thoracique et qui sont classés comme présentant un risque intermédiaire d'effets indésirables selon le score HEART. Bien que l'hospitalisation de ces patients permette une investigation et un traitement en temps opportun, il s'agit d'un processus exigeant en ressources. Cette étude examine si les patients ayant un score HEART intermédiaire peuvent être pris en charge en toute sécurité en ambulatoire par des cliniques d'accès rapide aux douleurs thoraciques. MéTHODES: Cette étude observationnelle rétrospective a inclus tous les patients souffrant de douleurs thoraciques aux urgences orientés vers des cliniques d'accès rapide de janvier 2018 à avril 2020 à Regina et Saskatoon, en Saskatchewan. Les scores HEART des médecins des urgences ont été utilisés à la place des scores HEART des examinateurs lorsqu'ils étaient disponibles. Le principal résultat était le taux d'événements coronariens indésirables majeurs (MACE), une mesure composite du décès, du syndrome coronarien aigu, de l'accident vasculaire cérébral, de l'angiographie coronaire et de la revascularisation à 6 semaines chez les patients à risque intermédiaire. Les résultats secondaires étaient le type de MACE, le taux de MACE avant un rendez-vous à la clinique d'accès rapide et la composante la plus prédictive du score HEART. RéSULTATS: Il y a eu 1989 orientations vers les urgences, dont 817 pour des patients à risque intermédiaire. 9,3 % des patients à risque intermédiaire ont subi un MACE à 6 semaines. Un MACE est survenu avant le suivi clinique d'accès rapide chez 1,1 % des patients à risque intermédiaire, la coronarographie étant le MACE le plus fréquent. À l'exclusion de l'angiographie coronarienne, le risque de MACE avant le suivi clinique d'accès rapide était de 0,7 % chez les patients à risque intermédiaire. Les composants du score HEART les plus prédictifs de MACE étaient la troponine (OR 11,0, IC 95 % : 3,7-32,3) et les antécédents (5,3, IC 95 % : 2,4-11,8). CONCLUSION: Cette étude démontre que les cliniques d'accès rapide sont probablement une alternative sûre à l'admission pour les patients souffrant de douleurs thoraciques à risque intermédiaire et pourraient réduire les admissions coûteuses de patients hospitalisés pour des douleurs thoraciques. En excluant l'angiographie, les taux de MACE étaient bien inférieurs au seuil de 2 % cité par l'American College of Emergency Physicians.

The COVID-19 Pandemic and Coronary Angiography for ST-Elevation Myocardial Infarction, Use of Mechanical Support, and Mechanical Complications in Canada: A Canadian Association of Interventional Cardiology National Survey.

BACKGROUND: As a result of the COVID-19 pandemic first wave, reductions in ST-elevation myocardial infarction (STEMI) invasive care, ranging from 23% to 76%, have been reported from various countries. Whether this change had any impact on coronary angiography (CA) volume or on mechanical support device use for STEMI and post-STEMI mechanical complications in Canada is unknown. METHODS: We administered a Canada-wide survey to all cardiac catheterization laboratory directors, seeking the volume of CA use for STEMI performed during the period from March 1 2020 to May 31, 2020 (pandemic period), and during 2 control periods (March 1, 2019 to May 31, 2019 and March 1, 2018 to May 31, 2018). The number of left ventricular support devices used, as well as the number of ventricular septal defects and papillary muscle rupture cases diagnosed, was also recorded. We also assessed whether the number of COVID-19 cases recorded in each province was associated with STEMI-related CA volume. RESULTS: A total of 41 of 42 Canadian catheterization laboratories (98%) provided data. There was a modest but statistically significant 16% reduction (incidence rate ratio [IRR] 0.84; 95% confidence interval 0.80-0.87) in CA for STEMI during the first wave of the pandemic, compared to control periods. IRR was not associated with provincial COVID-19 caseload. We observed a 26% reduction (IRR 0.74; 95% confidence interval 0.61-0.89) in the use of intra-aortic balloon pump use for STEMI. Use of an Impella pump and mechanical complications from STEMI were exceedingly rare. CONCLUSIONS: We observed a modest 16% decrease in use of CA for STEMI during the pandemic first wave in Canada, lower than the level reported in other countries. Provincial COVID-19 caseload did not influence this reduction.

INTRODUCTION: Après la première vague de la pandémie de COVID-19, de nombreux pays ont déclaré une réduction de 23 % à 76 % des soins invasifs de l'infarctus du myocarde avec élévation du segment ST (STEMI). On ignore si ce changement a entraîné des répercussions sur le volume d'angiographies coronariennes (AC) ou sur l'utilisation des dispositifs d'assistance mécanique lors de STEMI et des complications mécaniques post-STEMI au Canada. MÉTHODES: Nous avons réalisé un sondage pancanadien auprès de tous les directeurs de laboratoire de cathétérisme cardiaque pour obtenir le volume d'utilisation des AC lors des STEMI réalisées durant la période du 1er mars 2020 au 31 mai 2020 (période de pandémie) et durant 2 périodes témoins (1er mars 2019 au 31 mai 2019 et 1er mars 2018 au 31 mai 2018). Le nombre de dispositifs d'assistance ventriculaire gauche utilisés et le nombre de cas de communications interventriculaires et de ruptures du muscle papillaire diagnostiqués ont également été enregistrés. Nous avons aussi évalué si le nombre de cas de COVID-19 enregistrés dans chaque province était associé au volume d'AC liées aux STEMI. RÉSULTATS: Au total, 41 des 42 laboratoires canadiens de cathétérisme (98 %) ont fourni des données. Lors de la comparaison de la première vague de la pandémie aux périodes témoins, nous avons noté une réduction modeste, mais significative, sur le plan statistique de 16 % (ratio du taux d'incidence [RTI] 0,84; intervalle de confiance à 95 % 0,80-0,87) des AC lors de STEMI. Le RTI n'était pas associé au nombre provincial de cas de COVID-19. Nous avons observé une réduction de 26 % (RTI 0,74; intervalle de confiance à 95 % 0,61-0,89) de l'utilisation de pompes à ballonnet intra-aortique lors de STEMI. L'utilisation d'une pompe Impella et les complications mécaniques après les STEMI étaient extrêmement rares. CONCLUSIONS: Nous avons observé une diminution modeste de 16 % de l'utilisation des AC lors de STEMI durant la première vague de la pandémie au Canada, soit une diminution plus faible que ce que les autres pays ont signalé. Le nombre provincial de cas de COVID-19 n'a pas influencé cette réduction.

Inequity in Access to Transcatheter Aortic Valve Replacement: A Pan-Canadian Evaluation of Wait-Times.

BACKGROUND: There has been an exponential increase in the demand for transcatheter aortic valve replacement (TAVR). Our goal was to examine trends in TAVR capacity and wait-times across Canada. METHODS: All TAVR cases were identified from April 1, 2014, to March 31, 2017. Wait-time was defined as the duration in days from the initial referral to the TAVR procedure. TAVR capacity was defined as the number of TAVR procedures per million population/province/fiscal year. We performed multivariable multilevel Cox proportional hazards modelling of the time to TAVR as the dependant variable and the effect of provinces as random effects. We quantified the variation in wait-times among provinces using the median hazard ratio. RESULTS: We identified a total of 4906 TAVR procedures across 9 provinces. Despite a year over year increase in overall capacity, there was a greater than 3-fold difference in capacity between provinces. Crude median wait-times increased over time in all provinces, with marked variation from 71.5 days in Newfoundland to 190.5 and 203 days in Manitoba and Alberta, respectively. This suggests increasing demand outpaced the growth in capacity. We found a median hazard ratio of 1.62, indicating that in half of the possible pairwise comparisons, the time to TAVR for identical patients was at least 62% longer between different provinces. CONCLUSION: We found substantial geographic inequity in TAVR access. This calls for policy makers, clinicians, and administrators across Canada to address this inequity through revaluation of provincial funding mechanisms, as well as implementation of efficient care pathways.

Characteristics and usefulness of unintended premature ventricular contraction during invasive assessment of aortic stenosis.

BACKGROUND: Postextrasystolic potentiation (PESP)-associated augmentation in left ventricular-aorta pressure gradient (LVAoG) observed after incidental premature ventricular contraction (PVC) during resting echocardiography is similar to dobutamine stress echocardiography (DSE)-associated augmentation in LVAoG in patients with low-flow, low-gradient (LF-LG) aortic stenosis (AS). What is not known is whether a similar relationship exists when unintended PVC causes PESP during cardiac catheterization in patients with AS. METHODS: We retrospectively reviewed all catheterizations performed for patients with at least moderate AS who had LVAoG assessment. Univariate and multivariate analyses were conducted to determine the predictors of pre- and post-PVC mean LVAoG ≥ 40 mmHg. RESULTS: Between September 2015 to September 2017, of 140 individuals undergoing cardiac catheterization, 34 met study criteria. Mean pre-PVC gradient was 38.9 ± 22.8 mmHg. All patients exhibited PESP-associated augmentation of LVAoG by an average of 28 ± 12%. In multivariate analysis, the only significant predictor of post-PVC mean LVAoG ≥ 40 mmHg was preserved LV function (OR 6.81; 95% CI 1.41-32.82, p = 0.02). Inability to generate ≥ 40 mmHg of mean LVAoG post-PVC had 100% specificity for nonsevere AS in our observational cohort. CONCLUSIONS: Unintended but interpretable PVCs occurred in one in four patients with AS undergoing cardiac catheterization with measurable hemodynamics. All of our patients with PVCs, regardless of underlying LVEF, exhibited PESP-associated augmentation of LVAoG. Our exploratory analysis suggests that inability to generate ≥40 mmHg of mean LVAoG post-PVC is highly specific for nonsevere AS.

Long-term pharmacodynamic effects of Ticagrelor versus Clopidogrel in fibrinolytic-treated STEMI patients undergoing early PCI.

The long-term pharmacodynamic effects of Ticagrelor versus Clopidogrel in patients undergoing early percutaneous coronary intervention (PCI) after fibrinolytic therapy is unknown. From May 2014 to August 2016, 212 patients undergoing PCI within 24 h of Tenecteplase (TNK), Aspirin, and Clopidogrel for ST-elevated myocardial infarction (STEMI) were randomized at four Canadian sites to receive additional Clopidogrel or Ticagrelor initiated prior to PCI. The platelet reactivity units (PRU) were measured with the VerifyNow Assay before study drug administration (baseline), at 4 and 24 h post PCI, and follow-up appointment. A mixed-model analysis with time as the repeated measure and drug as the between-subjects factor was calculated using 2 separate 1 × 4 ANOVAs, with students t-tests used to compare drugs within each time point. Complete clinical follow-up data (median 115.0 days; IQR 80.3-168.8) was available in 50 patients (23.6%) randomized to either Clopidogrel (n = 23) or Ticagrelor (n = 27). Analyses revealed significant decreases in PRU from baseline to 4 h (261.4 vs. 71.7; Mdiff = - 189.7; p < 0.001) to 24 h (71.7 vs. 27.7; Mdiff = - 44.0; p < 0.001) to end of follow-up (27.7 vs.17.9; Mdiff = - 9.9. p = 0.016) for those randomized to Ticagrelor and significant decreases in PRU only from baseline to 4 h (271.3 vs. 200.8; Mdiff = - 70.5, p = < 0.001) in patients receiving Clopidogrel, and a significantly greater proportion of patients with adequate platelet inhibition (PRU < 208) on long-term follow-up (Clopidogrel, 82.6% vs. Ticagrelor, 100.0%; p = 0.038). Our results demonstrate that in patients undergoing PCI within 24 h of fibrinolysis for STEMI, Ticagrelor provides prolonged platelet inhibition compared with Clopidogrel.

Effects of ticagrelor versus clopidogrel on platelet function in fibrinolytic-treated STEMI patients undergoing early PCI.

OBJECTIVES: Patients undergoing PCI early after fibrinolytic therapy are at high risk for both thrombotic and bleeding complications. We sought to assess the pharmacodynamic effects of ticagrelor versus clopidogrel in the fibrinolytic-treated STEMI patients undergoing early PCI. METHODS AND RESULTS: Patients undergoing PCI within 24 hours of tenecteplase (TNK), aspirin, and clopidogrel for STEMI were randomized to receive additional clopidogrel 300 mg followed by 75 mg daily or ticagrelor 180 mg followed by 90 mg twice daily. The platelet reactivity units (PRU) were measured with the VerifyNow Assay before study drug administration (baseline) at 4 and 24 hours post-PCI. The primary end point was PRU ≤208 at 4 hours. A total of 140 patients (74 in ticagrelor and 66 in clopidogrel group) were enrolled. The mean PRU values at baseline were similar for the 2 groups (257.8±52.9 vs 259.5±56.7, P=.85, respectively). Post-PCI, patients on ticagrelor, compared to those on clopidogrel, had significantly lower PRU at 4 hours (78.7±88 vs 193.6±86.5, respectively, P<.001) and at 24 hours (34.5±35.0 and 153.5±75.5, respectively, P<.001). The primary end point was observed in 87.8% (n=65) in the ticagrelor-treated patients compared to 57.6% (n=38) of clopidogrel-treated patients, P<.001. CONCLUSION: Fibrinolysis-treated STEMI patients who received clopidogrel and aspirin at the time of fibrinolysis and were undergoing early PCI frequently had PRU >208. In this high-risk population, ticagrelor provides more prompt and potent platelet inhibition compared with clopidogrel (Funded by Astra Zeneca; NCT01930591, https://clinicaltrials.gov/ct2/show/NCT01930591).

Southern Saskatchewan Ticagrelor Registry experience.

BACKGROUND: As ticagrelor enters into clinical use for acute coronary syndrome, it is important to understand patient/physician behavior in terms of appropriate use, adherence, and event rates. METHODS: The Southern Saskatchewan Ticagrelor Registry is a prospective, observational, multicenter cohort study that identifies consecutive patients started on ticagrelor. We aimed to evaluate both on- and off-label use, identify characteristics of patients who prematurely stop ticagrelor, and describe patient/physician behavior contributing to inappropriate stoppage of this medication. RESULTS: From April 2012 to September 2013, 227 patients were initiated on ticagrelor, with a mean age of 62.2±12.1 years. The participants were 66% men and had a mean follow up of 157.4±111.7 days. Seventy-four patients (32.4%) had off-label indications. Forty-seven patients (20.7%) prematurely stopped ticagrelor and were more likely to be older, women, nonwhite, present with shock, and complain of dyspnea. Twenty-six of the 47 patients stopped ticagrelor inappropriately because of patient nonadherence (18 patients) and physician advice (eight patients). A composite outcome event of death from vascular causes, myocardial infarction, or stroke occurred in 8.8% of the entire cohort and was more likely to occur in those older then 65 years, those presenting with cardiogenic shock, and those who prematurely stopped ticagrelor. CONCLUSION: In this real-world registry of patients started on ticagrelor, a third have off-label indications and a fifth prematurely stop the medication. Premature discontinuation was an independent predictor of major life-threatening bleeding and increased composite event rate of death from vascular causes, myocardial infarction, or stroke.

Canadian Cardiovascular Society guidelines for the diagnosis and management of stable ischemic heart disease.

This overview provides a guideline for the management of stable ischemic heart disease. It represents the work of a primary and secondary panel of participants from across Canada who achieved consensus on behalf of the Canadian Cardiovascular Society. The suggestions and recommendations are intended to be of relevance to primary care and specialist physicians with an emphasis on rational deployment of diagnostic tests, expedited implementation of long- and short-term medical therapy, timely consideration of revascularization, and practical follow-up measures.