Peter A. McCullough M.D.

McCullough, P. A., A. Vasudevan, M. Sathyamoorthy, J. M. Schussler, C. E. Velasco, L. R. Lopez, C. Swift, M. Peterson, J. Bennett-Firmin, R. Schiffmann and T. Bottiglieri (2017). “Urinary 11-Dehydro-Thromboxane B2 and Mortality in Patients With Stable Coronary Artery Disease.” Am J Cardiol 119(7): 972-977.

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Antiplatelet therapy with aspirin has been shown to reduce adverse outcomes in patients with coronary artery disease (CAD). Aspirin irreversibly inhibits platelet cyclooxygenase-1 and attenuates thromboxane A2 (TXA2)-mediated platelet aggregation, but there is variable suppression of cyclooxygenase-1. From a cohort of patients with stable CAD, we performed blinded, detailed chart abstraction, and measured urinary 11-dehydro-thromboxane B2 (11dhTxB2), an inactive metabolite of TxA2 from frozen samples. There were 327 men (73%) and 122 women (27%) with a mean age (+/-SD) of 67 +/- 10 and 65 +/- 10 years, respectively. A positive linear trend for age was observed among tertiles of 11dhTxB2 (p trend = 0.01). Higher proportions of women (p = 0.001), chronic obstructive pulmonary disease (p trend = 0.0003), and heart failure (p trend = 0.003) were observed in the upper tertile of 11dhTxB2. Sixty-seven patients (14.9%) died over a median follow-up of 1,149 days and 87.5% of the deaths were due to cardiovascular causes. Twenty-six nonsurvivors (38.8%) were treated with P2Y12 receptor antagonists versus 161 survivors (42.2%; p = 0.61). By stepwise Cox proportional hazards analysis, we identified that patients in the middle (hazard ratio 7.14; 95% CI 2.46 to 20.68) and upper tertiles (hazard ratio 9.91; 95% CI 3.45 to 28.50) had higher risks for mortality after adjusting for age and co-morbidities. In conclusion, urinary concentration of 11dhTxB2 was a strong independent risk factor for all-cause mortality among patients with stable CAD on aspirin therapy and may be a marker for patients with CAD who require more intensive secondary prevention measures.

McCullough, P. A., A. Rios and B. Smith (2017). “Dialysis fistulas and heart failure.” Eur Heart J: 2017 Mar [Epub ahead of print].

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Defining the optimal care for patients reaching end-stage renal disease (ESRD) requiring haemodialysis continues to be a challenge for nephrologists, cardiologists, and vascular surgeons. It has been acutely recognized that temporary dialysis catheters used in ∼82% of those who start dialysis can be a nidus for intravascular infection and are associated with early mortality in ESRD.1 Accordingly, there has been a large emphasis on ‘fistula first’ or, in other words, having a permanent surgically created dialysis access conduit [arteriovenous fistula (AVF) or shunt with graft (AVG) material] and thus reducing the exposure to and the length of time with dialysis catheters.2 Permanent vascular access brings a new set of issues to the patient and physician, with complications such as low flow, clotting, infection, and need for revision.3,4 In this issue of the journal, Reddy and colleagues present data from 137 ESRD patients who underwent echocardiographic examinations before and 2.6 years after AVF/AVG creation.5 While there were modest improvements in left ventricular hypertrophy, access creation was associated with multiple adverse changes in right ventricular structure and function without a measurable increase in cardiac output.

McCullough, P. A., J. Zhang and C. Ronco (2017). “Volume expansion and contrast-induced acute kidney injury.” Lancet: 2017 Feb [Epub ahead of print].

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There is an ever-increasing population at risk of being exposed to intravascular iodinated contrast because of the increasingly popular practice of imaging techniques in medicine and surgery. Despite efforts to improve the safety of these agents, there has been no fundamental improvement in contrast product development since the introduction of iso-osmolar contrast more than 20 years ago.1; 2 ; 3 Thus, clinicians have focused on strategies to decrease the risk of contrast-induced acute kidney injury by limiting contrast volume, giving adjuvant agents, and providing supportive care once the renal damage has occurred. It has been suggested that intravascular volume expansion with isotonic crystalloid solution can decrease the incidence and the severity of contrast-induced acute kidney injury.4 This approach is attractive because the short-term administration of intravenous fluid results in an increase in renal blood flow, glomerular filtration, and increased volume of urine flow through the tubular segments of the nephron. Forced diuresis has been associated with a lesser rise in serum creatinine especially when higher rates (>150 ml/h) of urine flow have been achieved.5

Prasad, A., A. Sohn, J. Morales, K. Williams, S. R. Bailey, D. Levin, P. A. McCullough, R. Mehran, G. Lopez-Cruz and J. Harder (2017). “Contemporary practice patterns related to the risk of acute kidney injury in the catheterization laboratory: Results from a survey of society of cardiovascular angiography and intervention (scai) cardiologists.” Catheter Cardiovasc Interv 89(3): 383-392.

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OBJECTIVES: The goal of the present study was to survey the Society of Cardiovascular Angiography and Intervention (SCAI) member cardiologists to evaluate contemporary practice patterns with regards to contrast use, acute kidney injury (AKI) risk assessment, and prevention in patients undergoing invasive angiography. We sought to compare the physician responses against guideline statements and evidence-based data from clinical studies. METHODS: A 20-question online survey based on a modified Likert scale was sent out via email to the Society of Cardiovascular Angiography and Intervention (SCAI) member cardiologists. The survey questions focused on prophylaxis methods, medication management, risk assessment, contrast agent use, and postprocedure care. A scoring system was developed which examined the individual responses to analyze the 10 questions with the greatest strength of evidence in the literature and guidelines. RESULTS: The survey was completed by 506 individuals. Selected responses of note included the use of standardized volume expansion protocols: 64.8%, use of iso-osmolar contrast (iodixanol) in the majority of patients at risk of AKI: 55%, and 27% of individuals reported diluting contrast with saline for patients at risk of AKI during coronary angiography. For questions with support from guideline documents, 56.9% of the responses were scored as concordant with evidence-based data. Individuals who reported that the risk of AKI was often or always important in planning angiography for “at risk patients” were more likely to closely monitor renal function (76.7% vs. 40.0%, P = 0.003), obtain nephrology consultation (45.2% vs. 13.3%, P = 0.016) and use iso-osmolar contrast agents (56.0% vs. 26.7%, P = 0.033). CONCLUSIONS: The majority of cardiologists participating in this survey, reported practice patterns consistent with guideline and evidence-based recommendations. However, over 40% of responses to questions were inconsistent with these recommendations, suggesting continued opportunities for education and quality improvement concerning AKI prevention.

Elbehary, S., H. M. Szerlip and P. A. McCullough (2017). “Potassium excretion and outcomes in ckd: Is k intake ok?” Am J Kidney Dis 69(3): 325-327.

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Dietary potassium plays a pivotal role in blood pressure (BP), and higher potassium intake may subsequently decrease cardiovascular (CV) risk and mortality.1 In this issue of AJKD, Leonberg-Yoo et al 2 extend the epidemiologic evidence by relating dietary potassium intake with kidney disease progression and mortality in patients with chronic kidney disease (CKD).