Recurrent Stent Thrombosis Following Myocardial Infarction Associated With VITT-Like Antibodies

Early stent thrombosis is a rare complication of percutaneous intervention and is associated with significant 30-day mortality. We present a novel case of multiple recurrent early stent thrombosis consistent with spontaneous vaccine-induced thrombotic thrombocytopenia. We were successfully able to manage this unusual condition through an interdisciplinary collaboration.

CYP2C19 Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention in Diverse Clinical Settings

Background Studies have demonstrated increased risk of major atherothrombotic events in CYP2C19 loss-of-function (LOF) variant carriers versus non-carriers treated with clopidogrel after percutaneous coronary intervention (PCI). We sought to evaluate real-world outcomes with the clinical implementation of CYP2C19-guided antiplatelet therapy after PCI. Methods and Results Data from 9 medical centers where genotyping was performed in the setting of PCI were included. Alternative therapy with prasugrel or ticagrelor was recommended for patients with a CYP2C19 LOF variant. The primary outcome was the composite of major atherothrombotic events (all-cause death, myocardial infarction, ischemic stroke, stent thrombosis, or hospitalization for unstable angina) within 12 months following PCI. Moderate or severe/life-threatening bleeding within 12 months was a secondary outcome. Among 3342 patients, 1032 (31%) were LOF carriers, of whom 571/1032 (55%) were treated with alternative therapy. In LOF carriers, the rate of major atherothrombotic events was lower in patients treated with alternative therapy versus clopidogrel (adjusted HR, 0.56; 95% CI 0.39-0.82). In those without a LOF allele, no difference was observed (adjusted HR, 1.07; 95% CI 0.71-1.60). There was no difference in bleeding with alternative therapy versus clopidogrel in either LOF carriers or those without a LOF allele. Conclusions Real-world data demonstrate lower atherothrombotic risk in CYP2C19 LOF carriers treated with alternative therapy versus clopidogrel and similar risk in those without a LOF allele treated with clopidogrel or alternative therapy. These data suggest that PCI patients treated with clopidogrel should undergo genotyping so that CYP2C19 LOF carriers can be identified and treated with alternative therapy.

Transseptal Puncture Learning Curve for Transcatheter Edge-to-Edge Mitral Valve Repair

OBJECTIVE

This study examined the learning curve for transseptal puncture (TSP) during transcatheter edge-to-edge mitral valve repair (TEER) performed by a dedicated mitral valve structural heart team. Effective TSP is mandatory for TEER but can be time-consuming and associated with complications including pericardial effusion and cardiac tamponade.

METHODS

TSP was performed on 107 consecutive patients (76 ± 1 years, 52% male) undergoing TEER between 2014 and 2019. TSP was performed by each structural heart team member (1 cardiologist, 2 cardiac surgeons) on a rotating case-by-case basis. No team member had prior independent TSP experience. Data collected included total procedure time, TSP time (time elapsed between procedure start and septal crossing), and number of TSP attempts before successful puncture. Cumulative sum (CUSUM) of deviations from the mean across sequential cases were used to examine learning curves.

RESULTS

Median total procedure time was 107 min, and the median TSP time was 14 min. Greater case number was significantly associated with both lower TSP time (r _s = -0.22, P = 0.022) and lower total procedure time (r _s = -0.29, P = 0.003). The majority of patients required only 1 TSP attempt (79%). There was a significant quadratic relationship between case number and the CUSUM for TSP time, with the learning curve peaking at 49 cases.

CONCLUSIONS

TSP for TEER has a substantial learning curve, requiring >50 cases to achieve acceptable efficiency. Even once proficiency is demonstrated, TSP remains a time-consuming component of TEER. Improvements in transseptal access technology may significantly decrease the time needed to master TSP and may improve the safety and precision of the procedure.

Multisite Investigation of Strategies for the Implementation of CYP2C19 Genotype-Guided Antiplatelet Therapy

CYP2C19 genotype-guided antiplatelet therapy following percutaneous coronary intervention is increasingly implemented in clinical practice. However, challenges such as selecting a testing platform, communicating test results, building clinical decision support processes, providing patient and provider education, and integrating methods to support the translation of emerging evidence to clinical practice are barriers to broad adoption. In this report, we compare and contrast implementation strategies of 12 early adopters, describing solutions to common problems and initial performance metrics for each program. Key differences between programs included the test result turnaround time and timing of therapy changes, which are both related to the CYP2C19 testing model and platform used. Sites reported the need for new informatics infrastructure, expert clinicians such as pharmacists to interpret results, physician champions, and ongoing education. Consensus lessons learned are presented to provide a path forward for those seeking to implement similar clinical pharmacogenomics programs within their institutions.

Multisite Investigation of Outcomes With Implementation of CYP2C19 Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention

OBJECTIVES

This multicenter pragmatic investigation assessed outcomes following clinical implementation of CYP2C19 genotype-guided antiplatelet therapy after percutaneous coronary intervention (PCI).

BACKGROUND

CYP2C19 loss-of-function alleles impair clopidogrel effectiveness after PCI.

METHODS

After clinical genotyping, each institution recommended alternative antiplatelet therapy (prasugrel, ticagrelor) in PCI patients with a loss-of-function allele. Major adverse cardiovascular events (defined as myocardial infarction, stroke, or death) within 12 months of PCI were compared between patients with a loss-of-function allele prescribed clopidogrel versus alternative therapy. Risk was also compared between patients without a loss-of-function allele and loss-of-function allele carriers prescribed alternative therapy. Cox regression was performed, adjusting for group differences with inverse probability of treatment weights.

RESULTS

Among 1,815 patients, 572 (31.5%) had a loss-of-function allele. The risk for major adverse cardiovascular events was significantly higher in patients with a loss-of-function allele prescribed clopidogrel versus alternative therapy (23.4 vs. 8.7 per 100 patient-years; adjusted hazard ratio: 2.26; 95% confidence interval: 1.18 to 4.32; p = 0.013). Similar results were observed among 1,210 patients with acute coronary syndromes at the time of PCI (adjusted hazard ratio: 2.87; 95% confidence interval: 1.35 to 6.09; p = 0.013). There was no difference in major adverse cardiovascular events between patients without a loss-of-function allele and loss-of-function allele carriers prescribed alternative therapy (adjusted hazard ratio: 1.14; 95% confidence interval: 0.69 to 1.88; p = 0.60).

CONCLUSIONS

These data from real-world observations demonstrate a higher risk for cardiovascular events in patients with a CYP2C19 loss-of-function allele if clopidogrel versus alternative therapy is prescribed. A future randomized study of genotype-guided antiplatelet therapy may be of value.

Implementation of pharmacogenetics: the University of Maryland Personalized Anti-platelet Pharmacogenetics Program

Despite a substantial evidence base, implementation of pharmacogenetics into routine patient care has been slow due to a number of non-trivial practical barriers. We implemented a Personalized Anti-platelet Pharmacogenetics Program (PAP3) for cardiac catheterization patients at the University of Maryland Medical Center and the Baltimore Veterans Administration Medical Center Patients' are offered CYP2C19 genetic testing, which is performed in our Clinical Laboratory Improvement Amendment (CLIA)-certified Translational Genomics Laboratory. Results are returned within 5 hr along with clinical decision support that includes interpretation of results and prescribing recommendations for anti-platelet therapy based on the Clinical Pharmacogenetics Implementation Consortium guidelines. Now with a working template for PAP3, implementation of other drug-gene pairs is in process. Lessons learned as described in this article may prove useful to other medical centers as they implement pharmacogenetics into patient care, a critical step in the pathway to personalized and genomic medicine.

Acute coronary syndromes: from the emergency department to the cardiac care unit

Acute coronary syndromes result in a significant burden of morbidity and mortality in the United States. This spectrum of acute coronary thrombosis (including unstable angina, non-ST-segment elevation myocardial infarction, and ST-elevation myocardial infarction) has been well studied in large clinical trials. This review details the initial management of patients presenting with possible acute coronary syndromes in the context of care from the emergency department to the cardiac care unit. The importance of a rapid and focused evaluation, risk stratification, and appropriate therapies are discussed.

Evidence for early right ventricular and septal mechanical activation (interventricular dyssynchrony) in pulmonary hypertension

This study sought to characterize mechanical activation in pulmonary arterial hypertension (PAH) using 2-dimensional echocardiography with tissue Doppler imaging. Whether pathologic alterations of the right ventricle in PAH affect interventricular dyssynchrony due to changes in mechanical activation of the septum and the right ventricle is unclear. We studied 20 patients with PAH (14 women, mean age 55 +/- 16 years) and 20 healthy controls (15 women, mean age 41 +/- 11 years) that underwent tissue Doppler imaging between July 2006 and May 2007. PAH was associated with accelerated right ventricular (RV) (p <0.0001) and septal (p = 0.022) activation times, but no differences were found in lateral wall activation times between groups (p = 0.35). Measures of ventricular dyssynchrony indicated that patients with PAH had significantly lower RV-lateral wall delays (patients 3.2 +/- 66.2 ms vs controls 56.7 +/- 52.0 ms, p = 0.007), reflecting a faster activation of the right ventricle relative to the lateral wall than controls. In conclusion, PAH is associated with interventricular dyssynchrony manifested by accelerated RV free wall and septal activation times. Whether such dyssynchrony should serve as a therapeutic target remains to be determined.

Test-retest reliability of assessment for intraventricular dyssynchrony by tissue Doppler imaging echocardiography

The purpose of this study was to evaluate the test-retest reliability of intraventricular dyssynchrony (IVD) assessment by tissue Doppler imaging (TDI) echocardiography. Limited response rates to cardiac resynchronization may improve with TDI screening for appropriate recipients. However, the clinical applicability of TDI will depend on the reliability of the test. Repeat TDI was prospectively performed (11 +/- 11 days apart) in 15 patients with QRS intervals >120 ms and left ventricular ejection fractions <35% and 25 normal controls using the same machine, sonographer, and blinded readers for the 2 tests. There was no change in clinical status or treatment between tests. Established and clinically feasible criteria for IVD were evaluated. These were based on differences of TDI-derived activation time between 2, 4, or 12 left ventricular segments. Reliability was assessed by linear correlation and Bland-Altman analysis for quantified measures, along with percentage agreement and kappa statistics for IVD diagnosis. Despite good intrareader (r = 0.98, p <0.0001) and interreader (2 segments: r = 0.96, p <0.0001; 4 segments: r = 0.85, p <0.0001) reliability, test-retest correlations were uniformly modest for the 2-segment (r = 0.26, p = 0.11), 4-segment (r = 0.36, p = 0.021), and 12-segment (r = 0.50, p = 0.0009) measures. Test-retest agreement for IVD diagnosis by either criterion was equally limited (2 segments: 83%, kappa = 0.27; 4 segments: 75%, kappa = 0.47; 12 segments: 68%, kappa = 0.35). Bland-Altman analysis demonstrated wide confidence intervals, exceeding the diagnostic cutoff values for the respective criteria. In conclusion, the accurate assessment of IVD by TDI may be limited by poor test-retest reliability.

A double-blind placebo-controlled pilot study of controlled-release paroxetine on depression and quality of life in chronic heart failure

BACKGROUND

Depression is frequently observed in patients with heart failure and is associated with poor quality of life and adverse prognosis. However, the prevalence of depression in heart failure could be overestimated because symptoms of depression overlap with those of heart failure. Similarly, the importance of depression may be overestimated if depression merely reflects worse heart failure. Because the response to depression treatment has not been evaluated in this patient population, we evaluated the efficacy of controlled-release paroxetine (paroxetine CR), a selective serotonin reuptake inhibitor, on depression and quality of life in chronic heart failure.

METHODS

A double-blind, randomized, placebo-controlled design was used to evaluate reductions in depression following 12 weeks of treatment with paroxetine CR (n = 14, age 62.1 +/- 12.3 years) or placebo (n = 14, age = 61.9 +/- 9.0 years). Patients with symptomatic congestive heart failure and a score of at least 10 on the Beck Depression Inventory (BDI) were eligible. Beck Depression Inventory was obtained at baseline and 4, 8, and 12 weeks of follow-up. Quality of life was assessed using the Medical Outcomes Study Short Form and the Minnesota Living with Heart Failure Questionnaire.

RESULTS

Controlled-release paroxetine resulted in significantly more recovery from depression (BDI <10) than placebo (69% vs 23%, P = .018) and resulted in lower continuous BDI scores throughout the intervention (P = .024). Controlled-release paroxetine was associated with higher general health levels compared with placebo on the Medical Outcomes Study 36-Item Short Form survey (38 +/- 10 vs 30 +/- 6, P = .016) at 12 weeks of follow-up. Reductions in depression were correlated with improvements in psychological aspects of quality of life (P < .05) but not with physical quality of life measures (P > .10).

CONCLUSION

Antidepressant therapy with paroxetine CR results in significant reductions in depression among patients with heart failure. The reductions in depression with paroxetine CR are accompanied by improvements in psychological aspects of quality of life. Larger controlled trials are needed to further document the effectiveness of paroxetine CR and other selective serotonin reuptake inhibitors in patients with heart failure and to determine patient subgroups that are most likely to benefit from antidepressive interventions.

Cardiac risk assessment: matching intensity of therapy to risk

Simple RSS allow for rapid decision making in the emergency department. The data presented in this article suggest that for patients at the highest risk and the lowest risk for complications of NSTEACS, the scoring systems work well and allow effective triage and treatment. For patients at intermediate risk (30%-40% of all patients who have ACS), however, it is not clear whether early aggressive treatment with cardiac catheterization or routine conservative management should be the standard of care. The consensus guidelines are vague, and the scoring systems discriminate less well for these patients. The authors think that patients at intermediate risk are best served by initial screening with an RSS like the TRS (with risk scores of 3-4), followed by a multimarker strategy to define risk better. They also think that the next step is to design clinical trials to test strategies of care defined prospectively by risk. This step would, in the authors' opinion, begin the next round of the cycle of clinical therapeutics [31]. The treatment of patients who have NSTE ACS has been characterized in the past 2 decades by care based on evidence from many excellent clinical tri-als. The consensus panels have convened and guide patient management. Quality-improvement initiatives such as CRUSADE and GRACE give feedback to improve compliance with guidelines. The understanding of risk is developing with the help of these scoring systems. Discovery is ongoing. The next decade of acute cardiac care will focus on early identification of patients at high risk and on matching the most intensive treatments to the patients most in need. Excessive testing and care promotes cost inefficiency and, perhaps, increased hazard for some patients. New trials are needed to move these new hypotheses back into practice.

Sodium channel abnormalities are infrequent in patients with long QT syndrome: identification of two novel SCN5A mutations

Long QT syndrome (LQTS) is a heterogeneous disorder caused by mutations of at least five different loci. Three of these, LQT1, LQT2, and LQT5, encode potassium channel subunits. LQT3 encodes the cardiac-specific sodium channel, SCN5A. Previously reported LQTS-associated mutations of SCN5A include a recurring three amino acid deletion (DeltaKPQ1505-1507) in four different families, and four different missense mutations. We have examined the SCN5A gene in 88 index cases with LQTS, including four with Jervell and Lange-Nielsen syndrome and the remainder with Romano-Ward syndrome. Screening portions of DIII-DIV, where mutations have previously been found, showed that none of these patients has the three amino acid deletion, DeltaKPQ1505-1507, or the other four known mutations. We identified a novel missense mutation, T1645M, in the DIV; S4 voltage sensor immediately adjacent to the previously reported mutation R1644H. We also examined all of the additional pore-forming regions and voltage-sensing regions and discovered another novel mutation, T1304M, at the voltage-sensing region DIII; S4. Neither T1645M nor T1304M were seen in a panel of unaffected control individuals. Five of six T1304M gene carriers were symptomatic. In contrast to previous studies, QT(onset-c) was not a sensitive indicator of SCN5A-associated LQTS, at least in this family. These data suggest that mutations of SCN5A are responsible for only a small proportion of LQTS cases.

Multiple different missense mutations in the pore region of HERG in patients with long QT syndrome

Long QT syndrome (LQTS), is an inherited cardiac disorder in which ventricular tachyarrhythmias predispose affected individuals to syncope, seizures, and sudden death. Characteristic electrocardiographic findings include a prolonged QT interval, T wave alternans, and notched T waves. We have screened LQTS patients from 89 families for mutations in the pore region of HERG , the K+ channel gene previously associated with chromosome 7-linked LQT2. In six unrelated LQTS kindreds, single-strand conformation polymorphism analyses identified aberrant conformers in all affected family members. These conformers were not seen in over 100 unaffected, unrelated control individuals, suggesting that they represent pathogenic LQTS mutations. DNA sequence analyses of the aberrant conformers demonstrated that they reflect five different missense mutations: V612L, A614V, N629D, N629S, and N633S. The missense mutation A614V was found in two unrelated families. Further functional studies will be required to determine what effect each of these changes may have on HERG channel function.

Mutation of the gene for IsK associated with both Jervell and Lange-Nielsen and Romano-Ward forms of Long-QT syndrome

BACKGROUND

Long-QT syndrome (LQTS) is a disorder of ventricular repolarization characterized by a prolonged QT interval, syncope, seizures, and sudden death. Recently, three forms of LQTS have been shown to result from mutations in potassium or sodium ion channel genes: KVLQT1 for LQT1, HERG for LQT2, and SCN5A for LQT3. IsK, an apparent potassium channel subunit encoded by KCNE1 on chromosome 21, regulates both KVLQT1 and HERG. This relationship makes KCNE1 a likely candidate gene, because mutations of these genes are known to cause both the autosomal dominant Romano-Ward and recessive Jervell and Lange-Nielsen (JLN) forms of LQTS.

METHODS AND RESULTS

We screened 84 unrelated patients with Romano-Ward and 4 with JLN for possible mutations in KCNE1. We identified one homozygous mutation in a JLN patient that results in the nonconservative substitution of Asn for Asp at amino acid 76. The patient is congenitally deaf-mute, with recurrent syncopal events and a greatly prolonged QTc interval. The proband's mother and half-sister are both heterozygous for this mutation. Remarkably, both these family members have prolonged QTc intervals and would have been classified as Romano-Ward patients if not for the proband's diagnosis of JLN. This mutation was not identified in more than 100 control individuals.

CONCLUSIONS

These data provide strong evidence that KCNE1 mutations represent a fifth LQTS locus (LQT5). Further functional analysis, as well as the identification of more LQTS patients with KCNE1 mutations, will be important to confirm the role of IsK in LQTS.

Characterization of the complex between bovine osteocalcin and type I collagen

This study examined the association of bovine osteocalcin with type I collagen under a variety of conditions, including different buffers, pH, and concentrations of phosphate and Ca(II). The data showed that osteocalcin binds to type I collagen reversibly with a binding constant which varies from 4000 to 160,000 M(-1), depending upon the exact conditions. Furthermore, the results indicated that there is only one osteocalcin binding site per collagen molecule. The absence or presence of Ca(II) and/or phosphate in the buffer had little effect on complex formation.

Novel missense mutation in the cyclic nucleotide-binding domain of HERG causes long QT syndrome

Autosomal-dominant long QT syndrome (LQT) is an inherited disorder, predisposing affected individuals to sudden death from tachyarrhythmias. To identify the gene(s) responsible for LQT, we identified and characterized an LQT family consisting of 48 individuals. DNA was screened with 150 microsatellite polymorphic markers encompassing approximately 70% of the genome. We found evidence for linkage of the LQT phenotype to chromosome 7(q35-36). Marker D7S636 yielded a maximum lod score of 6.93 at a recombination fraction (theta) of 0.00. Haplotype analysis further localized the LQT gene within a 6.2-cM interval. HERG encodes a potassium channel which has been mapped to this region. Single-strand conformational polymorphism analyses demonstrated aberrant bands that were unique to all affected individuals. DNA sequencing of the aberrant bands demonstrated a G to A substitution in all affected patients; this point mutation results in the substitution of a highly conserved valine residue with a methionine (V822M) in the cyclic nucleotide-binding domain of this potassium channel. The cosegregation of this distinct mutation with LQT demonstrates that HERG is the LQT gene in this pedigree. Furthermore, the location and character of this mutation suggests that the cyclic nucleotide-binding domain of the potassium channel encoded by HERG plays an important role in normal cardiac repolarization and may decrease susceptibility to ventricular tachyarrhythmias.

Missense mutation in the pore region of HERG causes familial long QT syndrome

BACKGROUND

Long QT syndrome (LQT) is an inherited cardiac disorder that results in syncope, seizures, and sudden death. In a family with LQT, we identified a novel mutation in human ether-a-go-go-related gene (HERG), a voltage-gated potassium channel.

METHODS AND RESULTS

We used DNA sequence analysis, restriction enzyme digestion analysis, and allele-specific oligonucleotide hybridization to identify the HERG mutation. A single nucleotide substitution of thymidine to guanine (T1961G) changed the coding sense of HERG from isoleucine to arginine (Ile593Arg) in the channel pore region. The mutation was present in all affected family members; the mutation was not present in unaffected family members or in 100 normal, unrelated individuals.

CONCLUSIONS

We conclude that the Ile593Arg missense mutation in HERG is the cause of LQT in this family because it segregates with disease, its presence was confirmed in three ways, and it is not found in normal individuals. The Ile593Arg mutation may result in a change in potassium selectivity and permeability leading to a loss of HERG function, thereby resulting in LQT.