Back to Authors

So, Derek

https://orcid.org/0000-0002-3909-5698

Mayo Clinic

University of Ottawa

Citations 10

Sex Differences in Psychological Distress of Patients With Spontaneous Coronary Artery Dissection (SCAD): The MINDSET Study
Maukel, Lisa‐Marie , Coutinho, Thais D. , Mulvagh, Sharon L. , Madan, Mina , Pacheco, Christine , Bouchard, Karen , So, Derek , Saw, Jacqueline, Reed, Jennifer , Liu, Shuangbo , Sun, Louise Y. , Robert, Helen Mary, Lappa, N., Tulloch, Heather E., Bouchard, Karen , Reed, Jennifer L. , So, Derek Y , Saw, Jacqueline , E Tulloch, Heather , Liu, Shuangbo , Saw, Jacqueline , Paquin, Amélie , Robert, Helen, Tulloch, Heather

Circulation: Population Health and Outcomes | January 13, 2026 | Volume: 19 | Issue: 3 | Pages: No page available

10.1161/circoutcomes.125.012626 Get It

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndrome, predominantly affecting women. Psychological distress is common pre- and post-SCAD, yet sex-specific patterns remain understudied. This cross-sectional study aimed to examine sex differences in the psychological distress of patients with SCAD. METHODS: Adult patients diagnosed with SCAD within the past 3 years, confirmed by coronary angiography, were recruited from 6 Canadian hospitals between April 2022 and January 2025. Participants completed questionnaires assessing sociodemographics and validated measures of psychological distress: Patient Health Questionnaire-9 for depression, Generalized Anxiety Disorder-7 for generalized anxiety, Cardiac Anxiety Questionnaire for cardiac-related anxiety, and PTSD Checklist-5 for posttraumatic stress symptoms. Sex differences were analyzed using t tests for continuous variables and χ 2 tests for categorical variables. Multivariable linear regression models assessed the association between sex and psychological distress, adjusting for age, pre-SCAD mental health diagnosis, and employment status. RESULTS: Among 326 patients (92.9% women; mean age=53.3±11.1 years), women reported higher rates of preexisting mental health conditions (29.2% versus 8.7%; P =0.035). Post-SCAD women reported higher mean scores than men on the Patient-Health-Questionnaire-9, Cardiac-Anxiety-Questionnaire, and PTSD Checklist-5 (all P <0.05). Female sex was associated with greater depressive (B=2.94; P =0.010), cardiac anxiety (B=7.09; P =0.008), and posttraumatic stress symptoms (B=5.94; P =0.048) after adjustment. Clinically significant symptoms were more common in women versus men: 25.1% versus 0% (depression), 21.5% versus 4.4% (anxiety), 54.8% versus 26.1% (cardiac anxiety), and 15.5% versus 0% (posttraumatic stress). CONCLUSIONS: Both women and men experience clinically significant cardiac anxiety following SCAD, but women report a greater psychological burden, including more preexisting mental health conditions and twice the distress after SCAD. These results underscore the importance of routine psychological screening and timely intervention to support mental health and recovery outcomes, particularly among women.
Abstract 4341827: Double Trouble — Exploring Mental Health Issues in Patients with Spontaneous Coronary Artery Dissection (SCAD) and Fibromuscular Dysplasia (FMD)
Coutinho, Thais , Madan, Mina , So, Derek , Saw, Jacqueline , Wells, George A. , Sun, Louise Y. , Robert, Helen Mary, Lappa, N., Tulloch, Heather , Maukel, Lisa‐Marie , Mulvagh, Sharon L. , Pacheco, Christine , Bouchard, Karen , Reed, Jennifer L. , Liu, Shuangbo , Robert, Helen

Circulation | November 3, 2025 | Volume: 152 | Issue: Suppl_3 | Pages: No page available

10.1161/circ.152.suppl_3.4341827 Get It

Background: Spontaneous Coronary Artery Dissection (SCAD) is a cause of acute coronary syndrome, particularly among women, and is associated with psychological distress, including depression, anxiety, and post-traumatic stress (PTSD) symptoms. Fibromuscular dysplasia (FMD), a vascular condition that alters the arteries, is often found in patients with SCAD, adding complexity and uncertainty with a second serious diagnosis. This study examined the differences in mental health symptoms between SCAD survivors with and without FMD to better understand their unique psychosocial needs and inform interventions to enhance patient outcomes. Methods: Patients diagnosed with SCAD within the past 3 years were recruited from 6 Canadian cardiac hospitals. Participants completed questionnaires assessing socio-demographics, comorbidities, and validated psychological measures, including Patient Health Questionnaire-9 (PHQ-9) for depression, Generalized Anxiety Disorder-7 (GAD-7) for generalized anxiety, Cardiac Anxiety Questionnaire (CAQ) for cardiac-related anxiety, and PTSD Checklist (PCL-5) for PTSD symptoms. Differences in mental health outcomes between SCAD survivors with and without FMD were analyzed using t-tests for continuous variables and chi-square tests for categorical variables. Results: The study included 326 participants (92.9% female; mean age 53.3 years), with 67 participants (20.6%) having a confirmed diagnosis of FMD at the time of questionnaire completion (39.3% FMD at study completion). Post-SCAD, patients with FMD reported significantly higher scores than patients without FMD on the GAD-7 (6.4±5.9 vs. 4.7±4.9, p = .028), CAQ (29.9±13.1 vs. 26.0±12.3, p = .023), and PCL-5 (17.2±15.4 vs. 13.3± 14.0, p = .048). The proportion of SCAD survivors with FMD scoring in the clinically diagnostic range was significantly higher than those in patients without FMD: 32.8% vs. 20.8% for depression, 31.3% vs. 17.4% for anxiety, 64.2% vs. 49.2% for cardiac anxiety, and 25.4% vs. 11.6% for PTSD (all p < .05). Conclusions: Our findings suggest that SCAD survivors with comorbid FMD experience significantly higher distress —depression, generalized anxiety, cardiac-related anxiety, and PTSD symptoms—compared to those without FMD. Longitudinal research is needed to explore the role of these mental health concerns in long-term mental health and cardiac outcomes. Enhanced psychological interventions for those with FMD may be required.
Critical Care Cardiology Trials Network (CCCTN): a cohort profile
Metkus, Thomas S. , Baird-Zars, Vivian M., Alfonso, Carlos E., Alviar, Carlos L. , Barsness, Gregory W. , Bertić, Mia , Bohula, Erin A. , Burke, James A. , Burstein, Barry , Cooper, Howard A., Daniels, Lori B. , Goldfarb, Michael , Katz, Jason N. , Keeley, Ellen C. , Keller, Norma, Kenigsberg, Benjamin B. , Kontos, Michael C. , Lawler, Patrick R. , Leibner, Evan , Menon, Venu , Miller, P. Elliott , Newby, L. Kristin , O’Brien, Connor , Papolos, Alexander , Pierce, Matthew J, Prasad, Rajnish, Pisani, Barbara , Smith, Timothy D., Snell, R. Jeffrey, So, Derek , Ternus, Bradley , Teuteberg, Jeffrey J. , Zakaria, Sammy , Goldfarb, Michael , Pierce, Matthew , Fordyce, Christopher B , Goldfarb, Michael , Solomon, Michael A , van Diepen, Sean , Goldfarb, Michael , Lawler, Patrick , Daniels, Lori B , Bohula, Erin A , Zakaria, Sammy , O'Brien, Connor G , Pierce, Matthew J , Barnett, Christopher F. , Berg, David D. , Burke, James, Chaudhry, Sunit‐Preet , Fordyce, Christopher B. , Ghafghazi, Shahab , Kwon, Younghoon, Liu, Shuangbo , Prasad, Rajnish, Potter, Brian J , Roswell, Robert O. , Sinha, Shashank S , Shah, Kevin S , Solomon, Michael A. , Diepen, Sean van , Morrow, David A.

European Heart Journal - Quality of Care and Clinical Outcomes | August 27, 2022 | Volume: 8 | Issue: 7 | Pages: 703-708

10.1093/ehjqcco/qcac055 Get It

AbstractAimsThe aims of the Critical Care Cardiology Trials Network (CCCTN) are to develop a registry to investigate the epidemiology of cardiac critical illness and to establish a multicentre research network to conduct randomised clinical trials (RCTs) in patients with cardiac critical illness.Methods and resultsThe CCCTN was founded in 2017 with 16 centres and has grown to a research network of over 40 academic and clinical centres in the United States and Canada. Each centre enters data for consecutive cardiac intensive care unit (CICU) admissions for at least 2 months of each calendar year. More than 20 000 unique CICU admissions are now included in the CCCTN Registry. To date, scientific observations from the CCCTN Registry include description of variations in care, the epidemiology and outcomes of all CICU patients, as well as subsets of patients with specific disease states, such as shock, heart failure, renal dysfunction, and respiratory failure. The CCCTN has also characterised utilization patterns, including use of mechanical circulatory support in response to changes in the heart transplantation allocation system, and the use and impact of multidisciplinary shock teams. Over years of multicentre collaboration, the CCCTN has established a robust research network to facilitate multicentre registry-based randomised trials in patients with cardiac critical illness.ConclusionThe CCCTN is a large, prospective registry dedicated to describing processes-of-care and expanding clinical knowledge in cardiac critical illness. The CCCTN will serve as an investigational platform from which to conduct randomised controlled trials in this important patient population.
Sex‐Specific Differences in Clinical Outcomes After Percutaneous Coronary Intervention: Insights from the TAILOR‐PCI Trial
Madan, Mina , Abbott, J. Dawn , Lennon, Ryan J. , So, Derek , MacDougall, Andrea, McLaughlin, Mary Ann , Murthy, Vishakantha , Saw, Jacqueline , Rihal, Charanjit S. , Farkouh, Michael E. , Pereira, Naveen L. , Abdul‐Nour, Khaled, Dehghani, Payam , Doll, Josh, El‐Hajjar, Mohammed, Ginete, Wilson , Bachuwar, Alok, Graham, John, Guild, Cameron, Campbell, William W., Kostopoulis, Louie, Lane, Gary E. , Marzo, Kevin , O’Cochlain, Fearghas, Overgaard, Christopher B., Dzavik, Vlad, Raveendran, Ganesh , Reimers, Carl D., Garratt, Kirk N. , Saucedo, Jorge , Levisay, Justin , Suresh, D. P., Sweeney, John P., Tiong, Irving, Weitz, Steven, Wu, Alan H.B. , Lennon, Ryan J , So, Derek Y , Rihal, Charanjit S. , Goodman, Shaun G , Dawn Abbott, J , Goodman, Shaun G. , Abdul-Nour, Khaled, Darki, Amir , El-Hajjar, Mohammed C., Escobedo, Jorge , Frank, Adam, Goldberg, Ronald B , Campbell, William, Kim, Sang‐Wook , Lim, Hong‐Seok , Nazif, Tamim , Džavík, Vladimír , Razzouk, Louai , Reimers, Carl, Suresh, D.P., Weitz, Steven

Journal of the American Heart Association | June 14, 2022 | Volume: 11 | Issue: 12 | Pages: No page available

10.1161/jaha.121.024709 Get It

Background TAILOR‐PCI (Tailored Antiplatelet Initiation to Lessen Outcomes due to decreased Clopidogrel Response After Percutaneous Coronary Intervention) studied genotype‐guided selection of antiplatelet therapy after percutaneous coronary intervention versus conventional therapy with clopidogrel. The presence of CYP2C19 loss‐of‐function alleles in patients treated with clopidogrel may be associated with increased risk for ischemic events. We report a prespecified sex‐specific analysis of genotyping and associated cardiovascular outcomes from this study. Methods and Results Associations between sex and major adverse cardiac events (MACE: cardiovascular death, myocardial infarction, stroke, stent thrombosis, and severe recurrent ischemia) and Bleeding Academic Research Consortium (BARC) bleeding at 12 months were analyzed using Cox proportional‐hazards models. Among 5276 randomized patients, loss‐of‐function carriers were observed in ≈36% of both sexes, and >80% of carriers were heterozygotes. At 12 months, after adjustment for baseline differences, risks of MACE (HR , 1.28 [0.97 to 1.68]; P =0.088) and BARC bleeding (hazard ratio [HR], 1.36 [0.91 to 2.05]; P =0.14) were comparable among women and men. There were no significant interactions between sex and treatment strategy for MACE interaction P value ( P int =0.59) or BARC bleeding ( P int =0.47) nor for sex and genotype (MACE P int =0.15, and BARC bleeding P int =0.60). Conclusions CYP2C19 loss‐of‐function alleles were present in ≈1 in 3 women and men. Women had similar adjusted risks of MACE and bleeding as men following percutaneous coronary intervention. Genotype‐guided therapy did not significantly reduce the risk of MACE or bleeding relative to conventional therapy for both sexes. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01742117.
Abstract 10602: Baseline Clinical and Genetic Data Based Machine Learning Predictions of 1-Year Ischemic Outcomes Following Percutaneous Coronary Intervention
Raina, Anvi , Lennon, Ryan J. , Gulati, Rajiv , Rosenberg, Yves , So, Derek , Farkouh, Michael E. , Athreya, Arjun P. , Pereira, Naveen L. , Grant, Caroline, Goodman, Shaun G. , Lerman, Amir

Circulation | March 19, 2022 | Volume: 144 | Issue: Suppl_1 | Pages: No page available

10.1161/circ.144.suppl_1.10602 Get It

Background: Ischemic event rates are low after percutaneous coronary intervention (PCI), conversely second generation P2Y12 inhibitors increase bleeding therefore identifying patients at risk to enable precision in prescribing dual anti-platelet therapy (DAPT) is of clinical interest. Prior machine-learning predictive analyses have been limited by use of older generation stents and lack of genetic data. We utilized clinical and genetic data of patients with new generation stents enrolled in TAILOR-PCI, a 40-center international trial to predict ischemic events after PCI. Methods: There were 4398 eligible post PCI patients with acute coronary syndromes or stable coronary artery disease who were randomly split into training (n=3299) and validation (n=1099) cohorts. The primary endpoint comprising of cardiovascular death, myocardial infarction, stroke, or stent thrombosis within 12 months of PCI was predicted with patient characteristics prior to hospital discharge. First, random forests were used for feature selection with 1,000 bootstraps comprising equal numbers of those with and without ischemic events to minimize the bias of sample imbalance. Features were selected by a consensus on variable-importance over bootstraps. Second, using these features in the training cohort, support vector machines (SVM) with a polynomial kernel was trained with repeated 5-fold cross validation to choose a model with highest area under the receiver operating characteristic curve (AUC) which was then used to predict ischemic events in the validation cohort. Results: The primary endpoint occurred in 2.4% of patients. Using 89 clinical and genetic variables in the random-forest feature selection step, variable importance-based consensus identified 50 top predictors. These 50 predictors achieved AUC=0.703 in the SVM training cohort and AUC=0.744 (specificity=0.84; sensitivity =0.43) in the SVM validation cohort. Conclusions: Machine learning methods using baseline clinical and genetic data enables prediction of infrequent ischemic events in post PCI patients receiving new generation stents. The role of such artificial intelligence algorithms in individualization of DAPT by identifying high or low risk patients needs to be explored.
ABCD‐GENE Score and Clinical Outcomes Following Percutaneous Coronary Intervention: Insights from the TAILOR‐PCI Trial
Angiolillo, Dominick J. , Lennon, Ryan J. , Goodman, Shaun G. , Kim, Sang‐Wook , O’Cochlain, Fearghas, So, Derek , Sweeney, John P., Rihal, Charanjit S. , Farkouh, Michael E. , Pereira, Naveen L. , Capodanno, Davide , Angiolillo, Dominick J , Lennon, Ryan J , Goodman, Shaun G , Kim, Sang-Wook , O'Cochlain, Fearghas, So, Derek Y , Sweeney, John , Rihal, Charanjit S. , Pereira, Naveen L

Journal of the American Heart Association | February 8, 2022 | Volume: 11 | Issue: 4 | Pages: No page available

10.1161/jaha.121.024156 Get It

Background In TAILOR‐PCI, genotype‐guided selection of P2Y 12 inhibitors after percutaneous coronary intervention did not significantly reduce the risk of ischemic events at 12 months. The Age, Body Mass Index, Chronic Kidney Disease, Diabetes, and Genotyping (ABCD‐GENE) score identifies patients with high platelet reactivity on clopidogrel at increased risk of ischemic events. The aim of this study was to investigate the value of the ABCD‐GENE score for tailoring P2Y 12 inhibitor selection after percutaneous coronary intervention. Methods and Results In a post hoc analysis of the TAILOR‐PCI, outcomes were analyzed by ABCD‐GENE score and allocation to genotype‐guided or conventional P2Y 12 inhibitor selection. Primary (death, myocardial infarction, or stroke) and secondary (cardiovascular death, myocardial infarction, stroke, stent thrombosis, or severe recurrent ischemia) outcomes were assessed. Among 3883 patients discharged on clopidogrel in the genotype‐guided and conventional therapy groups, 15.8% and 84.2% had high (≥10 points) or low (<10) ABCD‐GENE scores, respectively. At 12 months, both the primary (5.2% versus 2.6%, P <0.001) and secondary outcomes (7.7% versus 4.6%, P =0.001) were significantly increased in patients with high ABCD‐GENE score. Among 4714 patients allocated to genotype‐guided or conventional therapy, the former did not significantly reduce the 12‐month risk of the primary and secondary outcomes in both the high and low ABCD‐GENE score groups (p interaction =0.48 and 0.27, respectively). Conclusions Among patients with percutaneous coronary intervention on clopidogrel, the ABCD‐GENE score was helpful in identifying those at higher risk. The ABCD‐GENE score may potentially enhance the precision of tailored selection of P2Y 12 inhibitors, which needs to be confirmed in prospective investigations. Clinical Trial Registration URL: http://www.clinicaltrials.gov . Unique Identifier: NCT01742117.
Performance of Plasma Adenosine as a Biomarker for Predicting Cardiovascular Risk
Jung, Richard G. , Santo, Pietro Di , Labinaz, Alisha, Gaudet, Chantal, Motazedian, Pouya , Parlow, Simon , Moreland, Robert B. , Marbach, Jeffrey A. , Boland, Paul , Promislow, Steven, Russo, Juan , Chong, Aun‐Yeong , So, Derek , Froeschl, Michael , May, Michel Le, Hibbert, Benjamin , Hibbert, Benjamin , Simard, Trevor , Ramirez, F. Daniel , Joseph, Joanne Emily , Moreland, Robert, May, Michel R. Le

Clinical and Translational Science | December 2, 2020 | Volume: 14 | Issue: 1 | Pages: 354-361

10.1111/cts.12886 Get It

Adenosine boasts promising preclinical and clinical data supporting a vital role in modulating vascular homeostasis. Its widespread use as a diagnostic and therapeutic agent have been limited by its short half‐life and complex biology, though adenosine‐modulators have shown promise in improving vascular healing. Moreover, circulating adenosine has shown promise in predicting cardiovascular (CV) events. We sought to delineate whether circulating plasma adenosine levels predict CV events in patients undergoing invasive assessment for coronary artery disease. Patients undergoing invasive angiography had clinical data prospectively recorded in the Cardiovascular and Percutaneous ClInical TriALs (CAPITAL) revascularization registry and blood samples collected in the CAPITAL Biobank from which adenosine levels were quantified. Tertile‐based analysis was used to assess prediction of major adverse cardiovascular events (MACE; composite of death, myocardial infarction, unplanned revascularization, and cerebrovascular accident). Secondary analyses included MACE subgroups, clinical subgroups and adenosine levels. There were 1,815 patients undergoing angiography who had blood collected with adenosine quantified in 1,323. Of those quantified, 51.0% were revascularized and 7.3% experienced MACE in 12 months of follow‐up. Tertile‐based analysis failed to demonstrate any stratification of MACE rates (log rank, P = 0.83), when comparing low‐to‐middle (hazard ratio (HR) 1.10, 95% confidence interval (CI) 0.68–1.78, P = 0.70) or low‐to‐high adenosine tertiles (HR 0.95, 95% CI 0.56–1.57, P = 0.84). In adjusted analysis, adenosine similarly failed to predict MACE. Finally, adenosine did not predict outcomes in patients with acute coronary syndrome nor in those revascularized or treated medically. Plasma adenosine levels do not predict subsequent CV outcomes or aid in patient risk stratification.
Transitioning a randomized controlled trial to a digital registry – experience from the TAILOR-PCI digital follow-up study on onboarding, engagement and geofencing consent rate
So, Derek , Iturriaga, Erin , Byrne, Jo , Lennon, Ryan J. , Geller, Nancy L. , Rihal, C., Bailey, Kent R. , Farkouh, Michael E. , Olgin, Jeffrey E. , Pereira, Nerison Lucas Costa, Avram, Robert , Byrne, J, Murthy, V, Goodman, Shaun G.

European Heart Journal | November 26, 2020 | Volume: 41 | Issue: Supplement_2 | Pages: No page available

10.1093/ehjci/ehaa946.3458 Get It

Abstract Background/Introduction TAILOR-PCI is the largest cardiovascular genotype-based randomized trial (NCT#01742117) investigating whether genotype-guided selection of oral P2Y12 inhibitor therapy improves ischemic outcomes after percutaneous coronary intervention (PCI). The TAILOR-PCI Digital Sub-Study tests the feasibility of extending original follow-up of 1 year to 2 years using state-of-the-art digital solutions. Deep phenotyping acquired during a clinical trial can be leveraged by extending follow-up in an efficient and cost-effective manner using digital technology. Purpose Our objective is to describe onboarding and engagement of participants initially recruited in a large, pragmatic, international, multi-center clinical trial to a digital registry. Methods TAILOR-PCI participants, within 23 months of their index PCI, were invited by letters containing a URL to the Digital Sub-Study website (http://tailorpci.eurekaplatform.org). These invitations were followed by phone calls, if no response to the letter, to determine reason for non-participation. A NIH-funded direct-to-participant digital research platform (the Eureka Research Platform) was used to onboard, consent and enroll participants for the digital follow-up. Participants were asked to answer health-related surveys at fixed intervals using the Eureka mobile app and desktop platform. To capture hospitalizations, participants could enable geofencing to allow background location tracking, which triggered surveys if a hospitalization was detected. Result(s) Letters were mailed to 893 of 929 eligible participants across 22 sites in the United States and Canada leading to 226 homepage visits and 118 registrations. There were 107 consents (12.0% of invited; mean age: 66.4±9.0; 19 females [18%]): 47 (44%) participants consented after the letter, 36 (34%) consented after the 1st call and 24 (22%) consented after a 2nd call. Among those who consented, 100 were eligible (7 did not have a smartphone) 81 downloaded the study mobile app and 73 agreed for geofencing (Figure 1). Among the 722 invited participants who were surveyed, 354 declined participation: due to lack of time (146; 20.2%), lack of smartphone (125; 17.3%), difficulty understanding (41; 5.7%), concern about using smartphone (34; 4.7%), concern of data privacy (14; 1.9%), concerns of location tracking (6; 0.8%) and other reasons (57; 7.9%). Conclusion Extended follow-up of a clinical trial using a digital platform is feasible but uptake in this study population was limited largely due to lack of time or a smartphone among participants. Based on data from other digital studies, uptake may also have been limited since digital follow-up consent was not incorporated at the time of consent for the main trial. Figure 1. Onboarding of the digital substudy Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institute of Health (NIH), National Heart, Lung, and Blood Institute (NHLBI)
Clopidogrel Pharmacogenetics
Pereira, Naveen L. , Rihal, Charanjit S. , So, Derek , Rosenberg, Yves , Lennon, Ryan J. , Mathew, Verghese, Weinshilboum, Richard M., Wang, Liewei , Baudhuin, Linnea M. , Hasan, Ahmed , Iturriaga, Erin , Fu, Yi-Ping, Geller, Nancy L. , Bailey, Kent R. , Farkouh, Michael E. , Rihal, Charanjit S. , Lennon, Ryan J. , Goodman, Shaun G. , Lerman, Amir

Circulation: Cardiovascular Interventions | April 11, 2019 | Volume: 12 | Issue: 4 | Pages: No page available

10.1161/circinterventions.119.007811 Get It

Common genetic variation in CYP2C19 (cytochrome P450, family 2, subfamily C, polypeptide 19) *2 and *3 alleles leads to a loss of functional protein, and carriers of these loss-of-function alleles when treated with clopidogrel have significantly reduced clopidogrel active metabolite levels and high on-treatment platelet reactivity resulting in increased risk of major adverse cardiovascular events, especially after percutaneous coronary intervention. The Food and Drug Administration has issued a black box warning advising practitioners to consider alternative treatment in CYP2C19 poor metabolizers who might receive clopidogrel and to identify such patients by genotyping. However, routine clinical use of genotyping for CYP2C19 loss-of-function alleles in patients undergoing percutaneous coronary intervention is not recommended by clinical guidelines because of lack of prospective evidence. To address this critical gap, TAILOR-PCI (Tailored Antiplatelet Initiation to Lessen Outcomes due to Decreased Clopidogrel Response After Percutaneous Coronary Intervention) is a large, pragmatic, randomized trial comparing point-of-care genotype-guided antiplatelet therapy with routine care to determine whether identifying CYP2C19 loss-of-function allele patients prospectively and prescribing alternative antiplatelet therapy is beneficial.