Heparin Dosing During Percutaneous Coronary Intervention and Obesity.

ABSTRACT: Unfractionated heparin is the most common anticoagulant used during percutaneous coronary intervention. Practice guidelines recommend an initial weight-based heparin bolus dose between 70 and 100 U/kg to achieve target activated clotting time (ACT) of 250-300 seconds. The impact of severe obesity on weight-based heparin dosing is not well studied. We performed a retrospective analysis of 424 patients undergoing percutaneous coronary intervention who received heparin for anticoagulation. We collected detailed data on cumulative heparin administration and measured ACT values in this cohort. We performed separate analyses to identify clinical predictors that may affect dose-response curves. There was significant variability in dosing with mean dose of 103.9 ± 32-U/kg heparin administered to achieve target ACT ≥ 250 seconds. Women received higher initial heparin doses when adjusted for weight than men (97.6 ± 31 vs. 89 ± 28 U/kg, P = 0.004), and only 49% of patients achieved ACT ≥ 250 s with the initial recommended heparin bolus dose (70-100 U/kg). Lower heparin dose (U/kg) was required in obese patients to achieve target ACT. In multivariate linear regression analysis with ACT as dependent variable, after inclusion of weight-based dosing for heparin, body mass index was the only significant covariate. In conclusion, there is significant variability in the therapeutic effect of heparin, with a lower weight-adjusted heparin dose required in obese patients.

Measures of social deprivation and outcomes after percutaneous coronary intervention.

BACKGROUND: Disparities in socioeconomic status are a frequently cited factor associated with worse cardiovascular outcomes. The social deprivation index (SDI) can be used to quantify socioeconomic resources at the population level. OBJECTIVES: The aim of this study was to assess the association of SDI with clinical outcomes following percutaneous coronary interventions (PCI). METHODS: This was a retrospective observational analysis of patients who underwent PCI and were included in a multicenter cardiac catheterization registry study. Baseline characteristics, congestive heart failure (CHF) readmission rates and survival were compared between patients with the highest and lower SDI. SDI was calculated based on the US community survey census tract-level data. RESULTS: Patients within the highest SDI quintile (n = 1843) had more comorbidities and a higher risk of death [hazard ratio (HR): 1.22 (95% confidence interval, CI: 1.1-1.39, p = 0.004); log rank: p = 0.009] and CHF readmission [HR: 1.56 (1.39-1.75, p < 0.001); log rank: p < 0.001) as compared with those in the lower quintiles (n = 10,201) during mean follow-up of 3 years. Increased risk of highest SDI for all-cause mortality and CHF remained significant after adjustment in multivariable analysis for factors associated with highest SDI. CONCLUSIONS: Patients within the highest SDI quintile had a greater proportion of comorbidities as well as higher risk for adverse outcomes as compared with patients with a lower SDI following PCI.

Factor XIII Val34Leu polymorphism and recurrent myocardial infarction in patients with coronary artery disease.

Factor XIII (FXIII) is necessary for cross linking of fibrin strands and generation of stable fibrin clot. FXIII Val34Leu is a common genetic single nucleotide polymorphism that has been associated with accelerated fibrin stabilization and reduced rate of fibrinolysis. The contribution of Val34Leu to long term risk of recurrent myocardial infarction (MI) in patients with coronary stenting has not been conclusively established. The objective of the study was to examine the effects of Val34Leu on fibrin generation, platelet aggregation, and long term clinical outcomes in patients with coronary artery disease treated with dual antiplatelet therapy. Patients with angiographically documented coronary artery disease who were treated with aspirin and clopidogrel were enrolled (n = 211). Light transmittance aggregometry and plasma fibrin clot formation using thrombelastography (TEG) were determined. Genotyping of Val34Leu was performed using Taqman assay. Clinical events during follow up were recorded. Homozygous carriers of 34 Leu variant had significantly shorter fibrin clot formation time as compared to wild type individuals (TEG K: 1.27 ± 0.3 vs. 1.68 ± 1.1 min, p = 0.011). The Val34Leu variant was associated with gene dose dependent increased risk of MI (log rank, p = 0.002) or occurrence of composite of MI and CV death (log rank, p = 0.005) with highest event rates observed in homozygous carriers of 34 Leu. In summary, FXIII Val34Leu polymorphism was associated with increased rate of fibrin stabilization in homozygous carriers of the variant and may increase risk of recurrent MI and death in patients with angiographically established coronary artery disease treated with dual antiplatelet therapy.

Prediction of Ischemic Events after Percutaneous Coronary Intervention: Thrombelastography Profiles and Factor XIIIa Activity.

BACKGROUND: High plasma fibrin clot strength (MA) measured by thrombelastography (TEG) is associated with increased risk of cardiac events after percutaneous coronary interventions (PCIs). Factor XIIIa (FXIIIa) cross-links soluble fibrin, shortens clot formation time (TEG-K), and increases final clot strength (MA). METHODS: We analyzed platelet-poor plasma from patients with previous PCI. Kaolin-activated TEG (R, K, MA) in citrate platelet-poor plasma and FXIIIa were measured (n = 257). Combined primary endpoint was defined as recurrent myocardial infarction (MI) or cardiovascular death (CVD). Relationship of FXIIIa and TEG measurements on cardiac risk was explored. RESULTS: FXIIIa correlated with TEG-MA (p = 0.002) and inversely with TEG-K (p < 0.001). High MA (≥35.35 mm; p = 0.001), low K (<1.15 min; p = 0.038), and elevated FXIIIa (≥83.51%; p = 0.011) were associated with increased risk of CVD or MI. Inclusion of FXIIIa activity and low TEG-K in risk scores did not improve risk prediction as compared with high TEG-MA alone. CONCLUSION: FXIIIa is associated with higher plasma TEG-MA and low TEG-K. High FXIIIa activity is associated with a modest increase in cardiovascular risk after PCI, but is less sensitive and specific than TEG-MA. Addition of FXIIIa does not provide additional risk stratification beyond risk associated with high fibrin clot strength phenotype measured by TEG.

Simultaneous administration of high-dose atorvastatin and clopidogrel does not interfere with platelet inhibition during percutaneous coronary intervention.

BACKGROUND: Reloading with high-dose atorvastatin shortly before percutaneous coronary interventions (PCIs) has been proposed as a strategy to reduce periprocedural myonecrosis. There has been a concern that statins that are metabolized by cytochrome P450 3A4 may interfere with clopidogrel metabolism at high doses. The impact of simultaneous administration of high doses of atorvastatin and clopidogrel on the efficacy of platelet inhibition has not been established. METHODS: Subjects (n=60) were randomized to receive atorvastatin 80 mg together with clopidogrel 600 mg loading dose (n=28) versus clopidogrel 600 mg alone (n=32) at the time of PCI. Platelet aggregation was measured at baseline, 4 hours after clopidogrel loading dose, and 16-24 hours after clopidogrel loading dose by light transmittance aggregometry using adenosine diphosphate as agonist. RESULTS: Platelet aggregation was similar at baseline in both the atorvastatin and the control groups (adenosine diphosphate 10 µM: 57%±19% vs 61%±21%; P=0.52). There was no significant difference in platelet aggregation between the atorvastatin and the control groups at 4 hours (37%±18% vs 39%±21%; P=0.72) and 16-24 hours post-clopidogrel loading dose (35%±17% vs 37%±18%; P=0.75). No significant difference in incidence of periprocedural myonecrosis was observed between the atorvastatin and control groups (odds ratio: 1.02; 95% confidence interval 0.37-2.8). CONCLUSION: High-dose atorvastatin given simultaneously with clopidogrel loading dose at the time of PCI does not significantly alter platelet inhibition by clopidogrel. Statin reloading with high doses of atorvastatin at the time of PCI appears to be safe without adverse effects on platelet inhibition by clopidogrel (ClinicalTrials.gov: NCT00979940).

Factors associated with poor survival in women experiencing cardiac arrest in a rural setting.

OBJECTIVES: The purpose of this study was to determine whether gender differences exist in the characteristics and outcomes for out-of-hospital cardiac arrest (OHCA) occurring in a rural setting. BACKGROUND: In urban settings, women have a lower incidence of OHCA than men but otherwise a comparable survival for ventricular fibrillation (VF) OHCA. Whether OHCA gender differences exist in rural settings is not clear. METHODS: The study consisted of a prospective collection and analysis of nontraumatic, adult OHCA prompting a 911 call in six rural Indiana counties. RESULTS: Over an average period of 2.2 years, 138 women and 250 men experienced OHCA (annual incidence rate: 56.4 per 100,000 men and 29.3 per 100,000 women). Women were older, less likely to experience OHCA in a public setting, more likely to be in an extended care facility, and less likely to have a witnessed arrest than were men. Women were less likely to present with an initial rhythm of VF than men (33.3% vs 53.6%, P < .001). Women in VF had a longer time interval from 911 call to first shock compared with men. Women had poorer survival to hospital discharge for all OHCA (2.2% vs 7.2%, P = .04) and VF OHCA (2.2% vs 13.4%, P = .05) compared with men. After age adjustment, female gender remained associated with a poorer OHCA survival outcome. With adjustment for all significant arrest characteristics, female gender was no longer associated with survival. CONCLUSIONS: In a rural population, women suffering OHCA have a dismal survival rate likely because of multiple unfavorable arrest characteristics.

Comparison of left ventriculography and coronary arteriography with positron emission tomography in assessment of myocardial viability.

BACKGROUND: Assessment of viability of myocardium after an ischemic insult is an important clinical question that affects decisions pertaining to potential revascularization. The results of contrast left ventriculograms and coronary angiography were compared to positron emission tomography (PET) in 64 patients with coronary artery disease and reduced left ventricular function. HYPOTHESIS: The study was undertaken to determine the relative utility of the invasive studies in the assessment of viability. METHODS: Right anterior oblique ventriculograms were assessed for hypokinesis, akinesis, or dyskinesis in six segments. The PET scans were assessed for viability by visual estimation of flourodeoxyglucose (FDG) uptake in six segments that corresponded to the segments analyzed on the ventriculograms. RESULTS: Of a total of 373 segments successfully analyzed by PET, 272 were judged to be viable (normal or hypokinetic) by contrast ventriculography. Of these, 253 (93%) were considered viable by PET. Of 177 segments deemed either normal or mild-to-moderately hypokinetic by ventriculography, 170 (94%) were viable by PET. Of 95 severely hypokinetic segments, 83 (84%) were viable by PET. Of 79 akinetic segments, 44 (56%) were considered viable by PET. For segments that were dyskinetic and thought to be nonviable by ventriculography, 19 of 22 (86%) were also considered nonviable by PET. For 294 segments for which a determination on viability was made based on the presence of wall motion on the ventriculogram (normal, hypokinetic, ordyskinetic; not akinetic), there was excellent agreement with PET (93%; p < 0.001). In 49 patients there was akinesis in no more than one segment in either the anterior or inferior territories, indicating the potential for assessment of viability by ventriculography in at least two of three segments in each territory. Coronary anatomy was analyzed to assess whether coronary patency could help in assessing viability. Segments supplied by patent arteries were more likely to be viable by PET than segments supplied by occluded arteries (p < 0.001). Akinetic segments were more likely to be supplied by occluded arteries (56 vs. 23, 72%). Dyskinetic segments were predominantly nonviable by PET (86%) and were usually supplied by occluded arteries (77%). CONCLUSION: In patients in whom the assessment of viability is clinically relevant, the presence of systolic inward motion on the contrast left ventriculogram correlates well with segment viability by PET, while outward or dyskinetic movement correlates well with nonviability. Thus, the use of PET to assess viability in many patients may be unnecessary.

C-reactive protein and fibrin clot strength measured by thrombelastography after coronary stenting.

Inflammation is implicated in the progression of coronary artery disease and the molecular processes of inflammation and thrombosis are closely intertwined. Elevated levels of C-reactive protein (CRP) have been associated with an elevated risk of adverse ischaemic events after coronary stenting and hypercoagulability. Heightened whole blood clot strength measured by thrombelastography (TEG) has been associated with adverse ischaemic events after stenting. We intended to examine the relationship of CRP to plasma fibrin clot strength in patients after coronary stenting. Plasma fibrin clot strength was measured by TEG in 54 patients 16-24 h after undergoing elective percutaneous coronary intervention (PCI). Coagulation was induced in citrated plasma by addition of kaolin and CaCl2. Plasma levels of CRP and fibrinogen were measured by enzyme-linked immunoassay. Increasing quartiles of CRP were associated with increasing levels of maximal plasma fibrin clot strength measured by TEG (P < 0.001) and increasing BMI (P = 0.04). Patients in the highest quartile of CRP had significantly higher maximal fibrin clot strength (G) than the patients in the lowest quartile (G: 3438 ±â€Š623 vs. 2184 ±â€Š576 dyn/cm, P < 0.0001). Fibrinogen concentration was not significantly different across quartiles of CRP (P = 0.97). Patients with established coronary artery disease undergoing coronary stenting who have elevated CRP after PCI exhibit heightened maximal plasma fibrin clot strength as compared with those with low CRP. Thrombotic risk associated with elevated CRP may be linked to procoagulant changes and high tensile fibrin clot strength independent of fibrinogen concentration.

Protease activated receptor-1 (PAR-1) mediated platelet aggregation is dependent on clopidogrel response.

INTRODUCTION: Clopidogrel inhibits ADP mediated platelet aggregation through inhibition of the P2Y12 receptor by its active metabolite. Thrombin induces platelet aggregation by binding to protease activated receptor-1 (PAR-1), and inhibition of PAR-1 has been evaluated in patients treated with clopidogrel to reduce ischemic events after acute coronary syndromes. Residual PAR-1 mediated platelet aggregation may be dependent on extent of clopidogrel response. MATERIAL AND METHODS: Platelet aggregation was measured in 55 patients undergoing elective PCI at 16-24 hours after 600 mg clopidogrel loading dose by light transmittance aggregometry using ADP 20 µM and thrombin receptor agonist peptide (TRAP) at 15 µM and 25 µM as agonists. Genomic DNA was genotyped for common CYP2C19 variants. RESULTS: Increasing quartiles of 20 µM ADP induced platelet aggregation after clopidogrel loading were associated with increasing levels of TRAP mediated platelet aggregation. Patients in the highest quartile (clopidogrel non-responders) of post treatment ADP aggregation had significantly higher TRAP mediated aggregation than the patients in the lowest quartile (clopidogrel responders) [TRAP 15 µM: 79.6 ± 5% vs. 69.5 ± 8%, p<0.001]. CONCLUSIONS: Non-responders to clopidogrel show increased residual platelet aggregation induced by TRAP, whereas clopidogrel responders exhibit attenuated response to TRAP. Addition of PAR-1 antiplatelet drugs may be most effective in patients with reduced clopidogrel response and high residual TRAP mediated platelet aggregation.

Cardiac events after non-cardiac surgery in patients with previous coronary intervention in the drug-eluting stent era.

The peri-operative risk for patients with coronary drug-eluting stents (DES) who subsequently have non-cardiac surgery (NCS) is unclear. We performed this retrospective study of all patients in our institution who had coronary intervention and subsequent NCS from 2003 through December 2008 to evaluate the incidence of major adverse cardiac events (MACE) in patients who received DES compared to those who received bare-metal stents (BMS) or had percutaneous transluminal coronary angioplasty (PTCA) during the same time period. The main outcome measures were 30-day post-operative myocardial infarction, stent thrombosis, target vessel revascularization (TVR) and cardiac death. During the 6-year study period, 1,770 coronary interventions were performed and 238 patients subsequently had NCS in 8 days to 49 months. Eighteen patients had PTCA, 79 BMS and 141 DES. Acute myocardial infarction occurred in 1 patient who had PTCA, 2 who had BMS and 14 who had DES (p = 0.10). Stent thrombosis occurred in 6 patients who had DES and none who had BMS (p = 0.09). Seven patients who had DES had TVR compared to 1 patient who had BMS and none who had PTCA (p = 0.41). Cardiac mortality occurred in 2 patients who had DES and none who had PTCA or BMS (p = 0.35). In conclusion, the 30-day MACE in patients who received coronary DES and undergone NCS were not significantly different compared to those who received BMS or had PTCA only, with a trend toward higher stent thrombosis in the DES group.

Takotsubo cardiomyopathy in a patient with esophageal cancer: a case report.

INTRODUCTION: Takotsubo cardiomyopathy has increasingly been reported in the medical literature in recent years. Much is still unknown regarding risk factors and clinical relationships. We contribute this case report to the growing set of literature on the topic. CASE PRESENTATION: We report the case of a 64-year-old woman with esophageal cancer who developed takotsubo cardiomyopathy, a form of reversible heart failure, and we present a review of the literature. Patients present with symptoms similar to an acute coronary syndrome; however, cardiac catheterization reveals patent coronary arteries, and symptoms of heart failure resolve completely within weeks. CONCLUSION: It is important that clinicians consider takotsubo cardiomyopathy in the differential diagnosis of heart failure and gain a basic understanding of the clinical presentation and diagnosis.

Combined distal embolization protection and rheolytic thrombectomy to facilitate percutaneous revascularization of totally occluded saphenous vein grafts.

Totally occluded saphenous vein grafts are difficult to treat percutaneously with a higher likelihood of distal embolization and slow-flow or no-reflow during percutaneous interventions. The PercuSurge system, which utilizes a distal balloon occlusive device, has been shown to improve clinical outcomes during saphenous vein graft (SVG) interventions. This device may not be optimal in the setting of heavy thrombus or debris burden, a situation frequently encountered in totally occluded SVGs. Rheolytic thrombectomy facilitates percutaneous interventions by effectively removing intraluminal thrombus and debris but lacks distal embolization protection. We report our experience with the synergistic use of balloon-based distal embolization protection (PercuSurge) and rheolytic thrombectomy (AngioJet) to optimize percutaneous revascularization of totally occluded SVGs.