Publications by authors named "Waqas Aftab"

11 Publications

  • Page 1 of 1

Prognostic implications of echocardiographic measures of left and right atrial pressures on survival in patients with end stage renal disease.

Echocardiography 2021 08 19;38(8):1290-1296. Epub 2021 Jul 19.

Loma Linda University Medical Center, Loma Linda, California, USA.

Background: Volume excess is common in patients with end stage renal disease (ESRD). We examined the prognostic value of clinical and echocardiographic measures of left (LA) and right atrial (RA) hypertension in this population.

Method: We prospectively collected demographic, clinical, pharmacological, echocardiographic data on 575 consecutive ESRD patients on hemodialysis undergoing cardiac evaluation before renal transplantation in a dedicated cardiac clinic. Survival was analyzed as a function of clinical and echocardiographic measures of LA and (RA) hypertension.

Result: Elevated LA pressure was seen in 48% of the patients based on E/e' velocity ratio of ≥ 15, and 28% had elevated RA pressure based on inferior vena caval size. Physical examination grossly underestimated the prevalence of both LA and RA hypertension. Atrial pressures were normal in 46% and both atrial pressures were elevated in 20% of the patients. Elevated LA pressure in the presence of normal RA pressure was found in 30%. Over a period of 20 ± 8 months, there were 43 deaths. There was a graded increase in mortality with increases in LA and bi-atrial hypertension (p = .009). The 2-year mortality rate was 6% in those with normal atrial pressures, 13% in those with isolated LA hypertension and 28% in those with bi-atrial hypertension.

Conclusion: Mitral E/e' ratio and inferior vena caval size are vastly more sensitive than physical examination for recognition of elevated atrial pressures and are strong predictors of survival in ESRD patients. Limited echocardiographic examination may have a role in ESRD patients undergoing dialysis to help achieve euvolemic status.
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http://dx.doi.org/10.1111/echo.15139DOI Listing
August 2021

Frequency of hypertensive response to dobutamine stress and diminished diagnostic value in patients with end-stage renal disease awaiting renal transplant.

Echocardiography 2021 02 24;38(2):162-168. Epub 2020 Nov 24.

Department of Cardiology, Loma Linda University Medical Center, Loma Linda, CA, USA.

Background: Patients with end-stage renal disease (ESRD) have a cardiovascular mortality about 15-30 times the general population and this is reduced by about 70% with renal transplant. Dobutamine stress echocardiography (DSE) is commonly performed for preoperative cardiac evaluation before renal transplantation. Hypertensive response during DSE occurs in about 1%-5% of DSE studies. However, it seems to be more frequent in patients with ESRD. But its frequency and clinical implications are not known.

Methods And Results: Of the 249-consecutive adult ESRD patients undergoing DSE for pre-kidney transplant cardiac risk assessment at our dedicated clinic, 53 (21%) had a hypertensive response. Half of the patients with a hypertensive response had stress-induced segmental wall motion abnormalities, of whom only half had angiographically significant coronary artery disease by quantitative coronary angiography. The hypertensive response was not a predictor of survival. Stress-induced segmental wall motion abnormalities predicted poor survival in those with a normotensive response, but not in those with a hypertensive response. The main and independent predictor of a hypertensive response was higher baseline systolic blood pressure (P < .0001).

Conclusions: Hypertensive response to dobutamine stress is common in ESRD patients and is not a predictor of survival. Stress-induced segmental wall motion abnormalities occur nearly thrice as frequently with a hypertensive response, but this is a poor predictor of angiographically significant coronary artery disease and does not predict survival.
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http://dx.doi.org/10.1111/echo.14932DOI Listing
February 2021

Healthcare outcomes in undocumented immigrants undergoing two emergency dialysis approaches
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Clin Nephrol 2017 Oct;88(10):181-192

Background: Current estimates suggest 6,500 undocumented end-stage renal disease (ESRD) patients in the United States are ineligible for scheduled hemodialysis and require emergent dialysis. In order to remain in compliance with Emergency Medicaid, an academic health center altered its emergency dialysis criteria from those emphasizing interdialytic interval to a set emphasizing numerical thresholds. We report the impact of this administrative change on the biochemical parameters, utilization, and adverse outcomes in an undocumented patient cohort.

Methods: This retrospective case series examines 19 undocumented ESRD patients during a 6-month transition divided into three 2-month periods (P1, P2, P3). In P1, patients received emergent dialysis based on interdialytic interval and clinical judgment. In P2 (early transition) and P3 (equilibrium), patients were dialyzed according to strict numerical criteria coupled with clinical judgment.

Results: Emergent criteria-based dialysis (P2 and P3) was associated with increased potassium, blood urea nitrogen (BUN), and acidosis as compared to P1 (p < 0.05). Overnight hospitalizations were more common in P2 and P3 (p < 0.05). More frequent adverse events were noted in P2 as compared to P1 and P3, with an odds ratio (OR) for the composite endpoint (intubation, bacteremia, myocardial infarction, intensive care unit admission) of 48 (5.9 - 391.2) and 16.5 (2.5 - 108.6), respectively. Per-patient reimbursement-to-cost ratios increased during criteria-based dialysis periods (P1: 1.49, P2: 2.3, P3: 2.49).

Discussion: Strict adherence to criteria-based dialysis models increases biochemical abnormalities while improving Medicaid reimbursement for undocumented immigrants. Alternatives to emergent dialysis are required which minimize cost, while maintaining dignity, safety, and quality of life.
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http://dx.doi.org/10.5414/CN109137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6102564PMC
October 2017

Survival Benefit of Statins in Hemodialysis Patients Awaiting Renal Transplantation.

Int J Angiol 2015 Jun;24(2):105-12

Division of Cardiovascular Medicine, Loma Linda University Medical Center, Loma Linda, California.

End-stage renal disease (ESRD) patients have extraordinarily high cardiovascular risk and mortality, yet the benefit of statins in this population remains unclear based on the randomized trials. We investigated the prognostic value of statins in a large, pure cohort of prospectively recruited patients with ESRD awaiting renal transplantation, and being followed up in a dedicated cardiac clinic. We prospectively collected demographic, clinical, laboratory, and pharmacological data on 423 consecutive ESRD patients on hemodialysis awaiting renal transplantation. Survival analysis was performed as a function of statin therapy. The baseline characteristics were as follows: age 57 ± 11 years, males 64%, diabetes mellitus in 68%, known coronary artery disease in 30%, left ventricular (LV) ejection fraction 61 ± 11%. Over a mean follow-up of 2 years, there were 43 deaths. Adjusted for age, gender, hypertension, body mass index, diabetes mellitus, coronary artery disease, smoking, and treatment with angiotensin converting enzyme inhibitor, β blocker, and antiplatelet medications, statin use was a predictor of lower mortality (hazard ratio 0.30, 95% confidence interval 0.11-0.79, p = 0.01). This beneficial effect of statin was supported by propensity score analysis (p = 0.02) and was consistent across all clinical subgroups. The benefit of statins seemed to be greater in those with LV hypertrophy and smoking. Statin therapy in hemodialysis patients awaiting renal transplant is independently associated with better survival supporting its use in this high-risk population.
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http://dx.doi.org/10.1055/s-0035-1547373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4452604PMC
June 2015

Predictors and prognostic implications of major adverse cardiovascular events after renal transplant: 10 years outcomes in 321 patients.

Int J Angiol 2014 Jun;23(2):131-8

Division of Cardiology, Loma Linda University Medical Center, Loma Linda, California.

Renal transplantation is the treatment of choice in patients with end-stage renal disease. Major adverse cardiac events (MACE) are common after renal transplant, especially in the perioperative period, leading to excess morbidity and mortality. The predictors and long-term prognostic implications of MACE are poorly understood. We analyzed predictors and implications of MACE in a cohort of 321 consecutive adult patients, who received renal allograft transplantation between 1995 and 2003 at our institution. The characteristics of 321 patients were: age at transplant 44 ± 13 years, 60% male, 36% diabetes mellitus (DM), left ventricular ejection fraction (LVEF) 60 ± 16%. MACE occurred in 21 patients with cumulative rate of 6.5% over 3 years after renal transplant, 57% occurring within 30 days, 67% within 90 days, and 86% within 180 days. MACE was not predicted by any clinical or pharmacological variables including age, gender, hypertension, DM, prior myocardial infarction, smoking, duration of dialysis, LVEF, or therapy with β-blockers (BB), angiotensin converting enzyme inhibitors, or calcium channel blockers. However, a clinical decision to perform a stress test or a coronary angiogram was predictive of higher MACE rate. MACE, irrespective of type, was independently associated with higher mortality over a period up to 15 years and this seemed to be blunted by BB therapy. MACE rate after renal transplantation decreases over time, most occurring in the first 90 days and is not predicted by any of the traditional risk factors or drug therapies. It is associated with higher long-term mortality.
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http://dx.doi.org/10.1055/s-0034-1372248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4082448PMC
June 2014

Beta and angiotensin blockades are associated with improved 10-year survival in renal transplant recipients.

J Am Heart Assoc 2013 Feb 19;2(1):e000091. Epub 2013 Feb 19.

Loma Linda University, Loma Linda, CA 92354, USA.

Background: Mortality in allograft kidney transplant recipients is high, and cardiovascular disease is the leading cause of death in these patients. They have heightened activity of sympathetic and renin-angiotensin systems. We tested the hypothesis that blockade of sympathetic and renin-angiotensin systems in these patients may offer a survival benefit using a large cohort of patients with long-term follow up.

Methods And Results: Medical records of 321 consecutive patients from our institution who had received renal transplantation between 1995 and 2003 were abstracted. Survival was analyzed as a function of pharmacological therapies adjusted for age, sex, and comorbidities. The characteristics of the 321 patients were as follows: age at transplant, 44±13 years; 40% male; 89% with hypertension; 36% with diabetes, and mean left ventricular ejection fraction of 60%. Over a follow-up of 10±4 years, there were 119 deaths. Adjusted for age, sex, diabetes, and coronary artery disease, use of a beta-blocker therapy (P=0.04) and angiotensin-converting enzyme inhibitor or receptor blocker (P=0.03) was associated with better survival. This treatment effect was seen across all major clinical subgroups and was supported by propensity score analysis. The propensity score-adjusted 10-year survival was 95% in those taking both groups of medications, 72% in those taking either of them, and 64% in those taking neither (P=0.004).

Conclusions: Use of beta-blocker and angiotensin blocking therapies is associated with higher survival after renal transplantation, indicating their potential protective role in this high-risk population.
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http://dx.doi.org/10.1161/JAHA.112.000091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603267PMC
February 2013

Acute cigarette smoke exposure reduces clot lysis--association between altered fibrin architecture and the response to t-PA.

Thromb Res 2010 Nov 1;126(5):426-30. Epub 2010 Sep 1.

Division of Cardiovascular Medicine, University of California San Francisco, Fresno, CA 93721, USA.

Background: Enhanced thrombolysis is a proposed mechanism for reduced mortality in cigarette smokers with STEMI ("smoker's paradox"). The mechanisms remain unclear but studies suggest fibrin architecture (FA) may affect thrombolysis. Our group has previously shown that acute cigarette smoke exposure (CSE) alters FA. This study was done to evaluate the association between FA, thrombolysis and CSE.

Methods And Results: Otherwise healthy smokers (n=22) were studied before and after smoking two cigarettes. Non-smokers (n=22) served as controls. Two ex-vivo models were used to evaluate clot lysis of venous blood and these data were compared to FA as determined by SEM. In the first model, clot lysis in a glass tube at 60minutes after addition of t-PA was measured. The second model quantified lysis utilizing thromboelastography. With the latter, after a clot reached maximum strength, t-PA was added and clot lysis at 60min was noted. SEM studies were performed on platelet poor plasma mixed with thrombin and FA was examined at 20K. Clot lysis was similar in both groups except that post-smoking, TEG showed a significantly lower lysis compared to pre- and non-smoking clots. SEM analysis showed significantly thinner fibers and denser clots post-smoking.

Conclusions: Venous clots from smokers failed to show an enhanced lysis when exposed to t-PA. In fact, acute CSE was associated with changes in FA and increased resistance to thrombolysis. These findings in part may explain enhanced thrombogenicity but suggest that mechanisms other than enhanced fibrinolysis are likely to be responsible for "smoker's paradox."
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http://dx.doi.org/10.1016/j.thromres.2010.07.021DOI Listing
November 2010

Frequency of elevated troponin I and diagnosis of acute myocardial infarction.

Am J Cardiol 2009 Jul 4;104(1):9-13. Epub 2009 May 4.

Division of Cardiology, UCSF Fresno Medical Education Program, Fresno, CA, USA.

This study evaluated the incidence and type of acute myocardial infarction (AMI) in a consecutive population with increased troponin I (TnI). AMI has recently been redefined and subclassified. Incidence, demographic data, angiographic findings, and hospital mortality of patients with various AMI subtypes or an increased TnI in the absence of AMI have not been previously reported in a prospective study. Over a 3-month period, all patients admitted from an emergency room or from in-patient services with >1 TnI level >0.04 ng/ml were evaluated and subclassified in AMI subgroups. In-hospital or recent coronary angiograms were reviewed. In-hospital mortality was noted. Of 2,944 patients with serial TnI measurements, 728 had an increased TnI and 701 (23.8%) were evaluated. Two hundred sixteen (30.8% with increased TnI and 42.7% with "rule-out MI" on admission) met criteria for AMI. One hundred forty-three (20.4%) had type 1, 64 (9.1%) had type 2, whereas 461 (65.8%) did not meet criteria for AMI. On multivariate analysis, use of angiography, peak TnI level, hyperlipidemia, and illicit drug use were independently associated with the diagnosis of AMI. TnI of 0.28 ng/ml had a 70% sensitivity and specificity for AMI diagnosis. In conclusion, a minority admitted with increased TnI have AMI by the universal definition. Type 1 is the most common AMI and is associated with higher TnI values and these patients are more likely to undergo angiography. Type 2 AMI is often associated with illicit drug use.
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http://dx.doi.org/10.1016/j.amjcard.2009.03.003DOI Listing
July 2009

Lyme carditis: sequential electrocardiographic changes in response to antibiotic therapy.

Int J Cardiol 2009 Oct 5;137(2):167-71. Epub 2008 Aug 5.

Lyme disease is a tick-borne spirochetal infection that may involve heart. The cardiac manifestations of Lyme disease including varying degrees of atrioventricular heart block occur within weeks to months of the infecting tick bite. This report describes a 43 year-old man with Lyme carditis who presented with complete heart block. The heart block resolved with ceftriaxone therapy. Lyme carditis should be considered in the differential diagnosis in patients who present with new onset advanced heart block.
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http://dx.doi.org/10.1016/j.ijcard.2008.05.028DOI Listing
October 2009
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