A 53-year-old man with atrial fibrillation underwent mitral and aortic mechanical valve replacements with St. Jude bileaflet tilting disk valves due to endocarditis in the setting of underlying rheumatic heart disease with moderate mitral stenosis. He was discharged on warfarin with an INR goal of 2.5-3.5.

Six months after being discharged from cardiac rehab, he saw a cardiologist for routine follow-up on warfarin 6 mg on Mon/Wed/Fri/Sun and 4 mg on Tues/Thurs/Sat; his most recent INR was 2.8. His cardiologist confirmed the INR target was 2.5-3.5.

The patient was seen monthly in the warfarin clinic for INR checks. The medical assistant (MA) charted that INR reports were sent to the cardiologist who reviewed reports and determined next doses of warfarin. The MA would then call the patient with the INR result and follow-up dosing instructions.

One month after the initial routine follow-up visit, the patient had an INR of 2.0 and he said that the MA told him an INR of 2.0-3.0 was "okay." The patient said he questioned this but was told the doctor was aware of the INR level and that he was to continue the same dose.

For each of the next two months, the INR was 2.2 and the patient was told to continue with the same dose. The next month, the INR was 3.0 and the patient was told to skip his warfarin dose that night.

One month later, his INR was 2.2 and he was told to continue the same dose. But five days after, he had sudden onset of right-sided numbness/weakness and slurred speech and was unable to walk. In the Emergency Department, his INR was 1.9 and blood pressure was 158/111 mm Hg. The weakness was resolving but the patient still had slurred speech.

A CT angiogram of his brain and neck was unremarkable, but an MRI showed an acute infarct at the junction of the left coronal radiata and thalamus with no intracranial hemorrhage. Neurology noted that the patient was not a tPA candidate. The symptoms and neurological findings resolved within four hours.

The patient filed a lawsuit against the cardiologist and the MA and expressed frustration that the warfarin clinic had been managing his warfarin with an INR goal of 2.0-3.0 instead of 2.5-3.5.

Of note, the cardiologist did not sign-off on many of the MA reports in the EHR until after the lawsuit was filed. While the cardiologist testified that the patient's target INR was always 2.5-3.5, it appears the cardiologist was not made aware of the patient's INR levels or did not note that the patient's level was not in the target range.

The case settled for a nominal amount.

"Three P" Analysis
The "Three P's" refer to the three key elements to reduce practitioner risk related to malpractice litigation.¹

Prevent Adverse Events
Current ACC guidelines recommend an INR target of 3.0 in patients with mechanical valve replacement with caveats only for patients who have newer generation valves and no other risk factors such as atrial fibrillation, previous thromboembolism, hypercoagulable state, and/or left ventricular systolic dysfunction.² In addition, it would be rare to have an MA running a warfarin clinic and more standard that it would be a licensed RN, LVN or pharmacist. Regardless of who is in this role, the supervising cardiologist must communicate frequently with her/him to ensure patients are managed appropriately.

Preclude a Malpractice Case Despite an Adverse Event
Even when it is appropriate for another clinician to directly manage a patient in the warfarin clinic, it is important that there be occasional direct conversations between the patient and cardiologist to both emphasize and corroborate the medication plan, and to answer any residual questions from the patient. In this case the patient had the understandable feeling that there was miscommunication within the team, leading him to question his care and likely contributing to his desire to file a claim.

Prevail in Lawsuits When a Claim is Made
Documentation of the communication between providers, in this case the MA and cardiologist, is critical to show they had a shared mental model regarding the patient's treatment plan. It may also alert clinicians to a disconnect and allow for correction of an errant treatment plan. While this case settled for a nominal amount, likely due to the resolution of the patient's stroke symptoms, had the patient's outcome been different, defense of the case would have been problematic.

The ACC has a longstanding relationship with the Doctor's Company to provide malpractice education, and also help ACC members save on malpractice coverage. Click here to learn more.

References

1. Feldman DL. Prevent, Communicate, Document: Medical Malpractice Data Help Us Manage Risk. The Doctor's Advocate. Available here.
2. Otto C, Nishimura R, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. J Am Coll Cardiol 2021;77:e25-e197.

The guidelines suggested here are not rules, do not constitute legal advice, and do not ensure a successful outcome. The ultimate decision regarding the appropriateness of any treatment must be made by each health care provider considering the circumstances of the individual situation and in accordance with the laws of the jurisdiction in which the care is rendered. This article was authored by John P. Erwin III, MD, FACC, the Louise W. Coon Chair, Department of Medicine, NorthShore University Health System and clinical professor, University of Chicago Pritzker School of Medicine, in IL, and member of ACC's Medical Professional Liability Insurance Workgroup, and David L. Feldman, MD, MBA, FACS, a plastic surgeon and the chief medical officer for The Doctor's Company and TDC Group in Napa, CA.