A Systematic Approach to the Evaluation of the Coronary Microcirculation Using Bolus Thermodilution: CATH CMD.

Coronary microvascular dysfunction (CMD) can cause myocardial ischemia in patients presenting with angina without obstructive coronary artery disease (ANOCA). Evaluating for CMD by using the thermodilution technique offers a widely accessible means of assessing microvascular resistance. Through this technique, 2 validated indices, namely coronary flow reserve and the index of microcirculatory resistance, can be computed, facilitating investigation of the coronary microcirculation. The index of microcirculatory resistance specifically estimates minimum achievable microvascular resistance within the coronary microcirculation. We aim to review the bolus thermodilution method, outlining the fundamental steps for conducting measurements and introducing an algorithmic approach (CATH CMD) to systematically evaluate the coronary microcirculation. Embracing a standardized approach, exemplified by the CATH CMD algorithm, will facilitate adoption of this technique and streamline the diagnosis of CMD.

Anatomical advantage to percutaneous insertion of the intra-aortic balloon through the left brachial artery over the right brachial artery.

Off-label use of the intra-aortic balloon (IAB) is not recommended in ideal situations and certainly not a Food and Drug Administration-approved activity. The instruction-for-use manual for the IAB recommends percutaneous insertion. However, there are certain extreme situations where "thinking outside the box" appears necessary. We have successfully inserted a transthoracic IAB (TIAB) in the operating room where an open sternum is an option. This has been instituted whenever severe peripheral vascular disease (PVD) precludes a percutaneous attempt or when attempted insertion fails. An open chest is not a choice in the catheterization laboratory or the postoperative setting. We have successfully inserted the IAB through the brachiall axillary artery in a patient with bilateral aortofemoral grafts, with a history of severe PVD, in the cardiac catheterization laboratory. A left-sided approach is advisable for brachial artery insertion and an axillary approach is also possible under sedation. This case report details our experience with transbrachial insertion of the IAB and establishes counterpulsation through this route as a viable option, where an open chest is not available and a percutaneous femoral approach has failed.

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.

Intraoperative coronary artery pulse Doppler patterns in patients with complete transposition of the great arteries undergoing the arterial switch operation.

BACKGROUND: Arterial switch operation is standard repair for complete transposition of the great arteries (TGA). Coronary artery abnormalities are the most common cause of morbidity and mortality in the acute postoperative phase. This study was designed to determine whether coronary artery pulse Doppler flow patterns obtained by transesophageal echocardiography during the arterial switch operation are correlated with acute postoperative outcomes. METHODS: A retrospective review of all patients with TGA undergoing the arterial switch operation between 2004 and 2006 was performed. Intraoperative coronary artery pulse Doppler flow patterns were analyzed by 2 blinded investigators. Associations of coronary artery pulse Doppler flow patterns with clinical outcomes were sought using multivariable linear and logistic regression analysis. RESULTS: Sixty-three patients (48 male, gestational age 38 +/- 2 weeks, birth weight 3,514 +/- 613 g) were analyzed. Three patients needed mechanical support (2 died), 19 had delayed sternal closure, 17 had arrhythmias, and 9 had ST changes. The most common coronary artery pulse Doppler flow pattern consisted of a late systolic peak followed by low-velocity flow throughout diastole. A left main coronary artery (LMCA) velocity time integral >0.14 (P = .01) and an LMCA peak systolic velocity >0.6 cm/s (P = .05) were associated with need for surgical revision. CONCLUSION: Abnormalities in LMCA flow were associated with the need for surgical revision in patients with TGA undergoing the arterial switch operation. Normal coronary artery pulse Doppler flow patterns after the arterial switch operation consisted of a late systolic peak followed by low-velocity flow throughout diastole.