Elsevier

Journal of Orthopaedics

Volume 14, Issue 4, December 2017, Pages 470-474
Journal of Orthopaedics

Clinical research study
Benign heart murmurs as a predictor for complications following total joint arthroplasty

https://doi.org/10.1016/j.jor.2017.07.009Get rights and content

Abstract

Background

There is scant literature examining the predictive role of heart murmurs in the absence of suspected structural heart disease on complications of non-cardiac surgery. We hypothesize the detection of heart murmurs in the absence of structural heart disease will help identify patients at risk for complications following total joint arthroplasty (TJA) surgery.

Method

This was a prospective cohort of patients undergoing TJA over a twenty-month period. The study was performed at a single academic institution with four subspecialty surgeons.

Patients undergoing primary TJA who were over eighteen years old, gave informed consent, and had adequate documentation were included in the study. Patients with a preoperative murmur or a newly discovered postoperative murmur were compared against patients with no murmur.

Surgery-related complications, performance with physical therapy, and discharge to a non-home facility were measured in each group.

Findings

345 (63%) eligible patients were included. 20 (5.8%) patients had a documented preoperative murmur and 36 (10.4%) patients had a new postoperative murmur. No patient had concern for major structural heart disease. Preoperative murmurs independently predicted development of acute kidney injury (OR 7.729, p < 0.001; RR 1.36). Preoperative murmurs also predicted likelihood to be discharged to a non-home facility (OR 2.97, p = 0.03; RR 1.87). New postoperative murmurs independently correlated with decreased performance with physical therapy (OR 0.466, p = 0.045; RR 0.664).

Interpretation

Detection of heart murmurs both preoperatively and postoperatively is a low cost strategy to identify post-TJA surgical patients at risk for postoperative acute kidney injury, decreased physical performance, and discharge to non-home facilities. These patients may benefit from early fluid resuscitation and renally-dosed post-operative medications.

Introduction

Growing demand, increasing healthcare costs, and higher financial penalties for complications of non-cardiac, elective surgery has amplified interest in low-cost strategies to identify patients at risk for post-operative complications.1 The cardiac exam is a low-cost screening method that may be a potential tool for identifying at-risk patients.2, 3 Heart murmurs associated with major structural heart defects are correlated with high complication rates following non-cardiac surgery,3, 4, 5 and current guidelines set forth by the American Heart Association and American College of Cardiology (AHA/ACC) recommend echocardiography if there is ‘moderate probability’ for structural heart disease associated with a murmur.5, 6 Although patients without suspected structural heart defects are usually deemed safe for elective surgery, there is no literature assessing the significance of low-grade, asymptomatic heart murmurs in patients with low-suspicion for structural disease.3 These murmurs are often considered benign and do not affect surgical planning. However, it is estimated that over 30% of elderly patients have systolic murmurs3, 7 and an unknown number of patients have transient murmurs following surgery, both with unknown significance regarding surgical outcomes. Total joint arthroplasty (TJA) represents a subset of elective surgeries that are notable for increasing demand, high costs, and bundled payments. By 2033 the demand for total knee arthroplasty and total hip arthroplasty is predicted to increase by 174% and 673%, respectively compared to 2007 numbers2, 8 and Medicare & Medicaid Services has made a goal of including half of all Medicare payments for TJA under a new payment model, such as bundled payments by 2018.9 Furthermore, TJA is a high-volume, reproducible surgery that allows for easy study comparison.

The purpose of this study was to prospectively assess the correlation between heart murmurs without suspicion of major structural heart defects and postoperative outcomes in TJA patients. Based on a pilot study, we hypothesized that heart murmurs would be associated with increased acute kidney injury (AKI) and decreased physical capacity following TJA.

Section snippets

Methods

This study was conducted with the approval of our Institutional Review Board. No outside funding was received. Written consent was given by all subjects, and no compensation was offered. This was a single-institution prospective cohort study including patients from four surgeons. Inclusion criteria were patients who underwent elective primary total hip or total knee arthroplasty between 4/1/14 and 12/15/15, were over the age of 18, spoke English, and provided informed consent. Patients were

Results

345 of 542 eligible patients (63%) were included in the study. 152 patients (28%) did not consent and 68 patients (12.5%) had inadequate documentation. The most common mode of inadequate documentation was that patients were evaluated by a hospitalist more than 24 h after surgery. The sample size exceeded the needed number calculated in the power analysis of 286 patients. 209 (60.5%) patients underwent total knee arthroplasty (TKA). 134 patients (38.8%) were male, the average age was 61.4 years,

Conclusion

Our study investigated the correlation between low-grade cardiac murmurs and postoperative outcomes following non-cardiac surgery, specifically TJA. We stratified murmurs as existing pre-operatively or newly-developed post operatively. We observed that preoperative murmurs independently predict postoperative AKI and correlate with discharge to a non-home facility. New postoperative murmurs are surprisingly common and independently correlate with decreased performance with physical therapy but

Conflict of interest

None.

Acknowledgements

The authors of this manuscript have no conflicts of interest to report. Author JF had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. JF and JA conducted all data analysis within this manuscript.

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