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Intersection Of Limb And Life Preservation: How An Infected Diabetic Foot Ulceration Led To Emergent Cardiac Intervention
Diabetes increases patient mortality rates by two- to four-fold compared to those without diabetes.1-5 These rates increase another two-fold in patients with a diabetic foot ulceration (DFU).1-4 Mortality rates in patients with a DFU range from 10 percent at 16 months to 24 percent at five years.1 Most fatalities in these patients occur due to cardiovascular disease, specifically a myocardial infarction.1-4,6 Patients with diabetes and a DFU, diabetes duration greater than 10 years, an elevated hemoglobin A1c, increased low-density lipoprotein (LDL) cholesterol levels, reduced high-density lipoprotein (HDL) cholesterol levels, and the presence of coronary artery disease, cerebrovascular disease, hypertension, and hypercholesteremia are all at significantly increased risk for a cardiac event compared to patients with diabetes and no DFU.2-4,7 Deaths also reportedly occur at a younger age in patients with diabetes and a DFU compared to those with diabetes that do not have a DFU. Patients with a neuroischemic DFU also have a greater mortality risk compared to patients with a neuropathic DFU without an ischemic component.1-3,7 Non-cardiovascular complications of a DFU, such as infection and sepsis, may also contribute to the increased risk for mortality secondary to a cardiac event.2-3 Another concern is that patients with diabetes can present asymptomatically in the midst of an acute cardiac event, the so-called “silent MI.”5,7 Asymptomatic cardiac events happen significantly more often in patients with diabetes and a DFU compared to patients with diabetes alone. Increased risk is also gender-dependent, occurring more often in women than men.7
Mortality rates further increase once amputation takes place. While these rates are greater with major lower extremity amputation than with minor amputation, mortality rates increase with both.8 This is due to the additional workload placed on an already compromised heart that occurs after amputation. Major lower extremity amputation is also associated with worse patient quality of life, as these patients often become non-ambulatory and unable to perform activities of daily living independently.8 Patients with diabetes, a DFU, and concurrent occurrence of a cardiac event require multidisciplinary treatment focused on limb and life-saving efforts. Presented here is the clinical course of an elderly male patient who presented with an infected DFU, and whose medical team subsequently determined he was also undergoing a symptomatic non-ST segment elevation myocardial infarction.
When Medical Evaluation Of A Patient With A DFU Reveals Unexpected Findings
An 82-year-old male presented to the Emergency Department with a chief concern of a DFU of the left plantar foot, generalized weakness, and midsternal chest pain with shortness of breath. The patient stated he first noticed the ulceration two days before, when his primary care physician (PCP) noted it on physical exam and recommended topical antibiotic ointment. His past medical history consisted of congestive heart failure, type 2 diabetes, hypertension, hyperlipidemia, gastroesophageal reflux, gout, peripheral arterial disease, benign prostate hypertrophy, depression, anxiety, insomnia, chronic pain, and constipation. His past surgical history consisted of an appendectomy, gastrointestinal surgery, and prostate surgery. He reported a history of intermittent claudication, walking only one to two blocks before experiencing pain in the lower extremity. The patient denied any history of cardiac procedures or previous episodes of chest pain or shortness of breath. He did relate a prior history of angioplasty to the left lower extremity six years prior, and former history of smoking, having quit using tobacco 30 to 40 years ago.
The patient had stable vital signs on examination. Focused examination of the left foot revealed non-palpable pulses at the posterior tibial and dorsalis pedis arteries with 2+ pitting edema to the dorsal foot. Doppler examination of the left foot revealed monophasic signals. There was a full-thickness ulceration with a fibrotic base and exposed muscle measuring 1.5 x 1.0 x 1.2 cm at the plantar aspect of the second metatarsal head. The ulcer did probe to bone. The ulcer exhibited hyperkeratotic margins with periwound erythema about the dorsal and plantar foot and purulent drainage. An electrocardiogram and echocardiogram were normal. However, given the patient’s symptoms and elevated troponins, he underwent a cardiac catheterization which found 80 to 90 percent occlusion of the left anterior descending artery. Multidisciplinary collaboration determined that the best course of action included emergent cardiac intervention and left foot incision and drainage for infection source control.
After admission, the patient underwent an emergent four-vessel coronary artery bypass and left foot incision and drainage consisting of partial amputation of the second and third rays. Negative pressure wound therapy began two days after the initial surgical procedure on the foot to assist with wound contracture and closure. Multidisciplinary collaboration continued with antibiotic therapy directed by infectious disease and adjuvant hyperbaric oxygen therapy. Discharge took place to a skilled nursing facility approximately three weeks after initial surgical intervention, where he resided for the next 90 days. The facility continued negative pressure wound therapy with dressing changes except when in the outpatient clinic during follow-up.
Application of an acellular human dermal allograft (AHDA) (Dermacell AWM,® LifeNet Health, Virginia Beach, VA) nine weeks after the initial procedure helped accelerate wound resolution. Incorporation of the first graft was occurring nicely prior to accidental removal of part of the graft five weeks post-application. A second graft application continued the expedited healing observed with the first graft. Complete wound resolution took place 14 weeks following the second application of the AHDM. The patient’s cardiac recovery was uneventful. He continues to follow up with his cardiologist and primary care provider.
Understanding The Interplay Of Cardiac Events And DFUs
Patients with diabetes have an increased mortality risk.1-5 The majority of fatalities in these patients occur due to myocardial infarction.1-4 Patients can undergo an acute cardiac event and remain asymptomatic. In a study of 134 patients with diabetes and a DFU, 78 percent had signs of cardiac dysfunction on echocardiogram.5 Of patients with no known history of cardiac disease, 76 percent had abnormal findings on echocardiogram. Given the potential for autonomic neuropathy to conceal symptoms of heart disease, presence of a foot ulceration in patients with diabetes is a proposed indicator of impaired cardiac function.5 Patients with a history of lower extremity revascularization or a toe pressure less than 60 mmHg also have a greater risk of left ventricular hypertrophy.5 Non-ST segment elevation myocardial infarction suggests the presence of cardiac artery narrowing and is a common occurrence in the elderly and those with diabetes.6 One report cited a 6.6 percent incidence of acute cardiac events within the first 30 days of hospitalization in patients presenting with infection or gangrene of the foot. This was the first time for diagnosis of cardiac disease in 33 percent of the patients.9
In the case presented here, the patient had a symptomatic non-ST segment elevation myocardial infarction with a normal electrocardiogram and echocardiogram. Coronary angiogram was performed due to the symptoms at presentation and elevated troponins found on laboratory examination. The patient also had a DFU of the left foot with previous history of angioplasty to the left lower extremity. He reported no history of cardiac symptoms or intervention. Cardiac catherization revealed significant cardiac disease requiring an emergent four-vessel coronary artery bypass.
Concluding Thoughts
Clinicians should consider an increased index of suspicion for the potential of significant cardiac events in patients presenting with a DFU. Concern and consideration for consultation for cardiac evaluation should increase with increased severity of the foot infection, presence of gangrene of the foot, patients with a diagnosis of diabetes greater than 10 years, an elevated Hemoglobin A1c, increased LDL levels, reduced HDL levels, coronary artery disease, cerebrovascular disease, hypertension, hypocholesteremia, and in female patients. Multidisciplinary treatment should occur, beginning with cardiac intervention, followed by a focus on limb-saving efforts. In the case presented here, rapid multidisciplinary patient assessment and intervention led to a successful limb and life-saving outcome.
Dr. Kalk is President of Affiliated Podiatrists, LTD and Director of Podiatric Residency Training at Swedish Hospital, part of NorthShore University Hospital in Chicago. He is board-certified by the American Board and Foot and Ankle Surgeons and American Board of Wound Management.
Dr. Marchand and Dr. Raj are third-year podiatric residents at Swedish Hospital, part of NorthShore University Hospital in Chicago.
Dr. Nguyen and Dr. Hussaini are second-year residents at Swedish Hospital, part of NorthShore University Hospital in Chicago.
Dr. Yeo and Dr. Czarnecki are first-year residents at Swedish Hospital, part of NorthShore University Hospital in Chicago.
Dr. Hickner is a graduated resident of Swedish Hospital, part of NorthShore University Hospital in Chicago.
Acknowledgement: The authors wish to acknowledge Valerie Marmolejo, DPM, MS, CTBS, MWC with Scriptum Medica for her assistance in manuscript development.
1. Chammas NK, Hill RL, Foster AV, Edmonds ME. Is neuropathic ulceration the key to understanding increased mortality due to ischaemic heart disease in diabetic foot ulcer patients? A population approach using a proportionate model. J Int Med Res. 2002;30(6):553-559.
2. Brownrigg JR, Davey J, Holt PJ, et al. The association of ulceration of the foot with cardiovascular and all-cause mortality in patients with diabetes: a meta-analysis. Diabetologia. 2012;55(11):2906-2912.
3. Brownrigg JR, Griffin M, Hughes CO, et al. Influence of foot ulceration on cause-specific mortality in patients with diabetes mellitus. J Vasc Surg. 2014;60(4):982-986.
4. Tuttolomondo A, Maida C, Pinto A. Diabetic foot syndrome as a possible cardiovascular marker in diabetic patients. J Diabetes Res. 2015;2015:268390.
5. Löndahl M, Katzman P, Fredholm O, Nilsson A, Apelqvist J. Is chronic diabetic foot ulcer an indicator of cardiac disease? J Wound Care. 2008;17(1):12-16.
6. Hung SY, Huang YY, Hsu LA, et al. Treatment for diabetic foot ulcers complicated by major cardiac events. Can J Diabetes. 2015;39(3):183-187.
7. Jenab Y, Mortez A, Nozari Y, Farokhian A, Ardekani JM, Nakhjavani M. Diabetic foot ulcer is a significant predictor of silent myocardial ischemia in women with type 2 diabetes. J Diabetes Metab. 2011;2:9.
8. Rathnayake A, Saboo A, Malabu UH, Falhammar H. Lower extremity amputations and long-term outcomes in diabetic foot ulcers: A systematic review. World J Diabetes. 2020;11(9):391-399.
9. Singh M, Khan K, Fisch E, et al. Acute cardiac events in patients with severe limb infection. Int J Low Extrem Wounds. 2018;17(4):261-267.
