Leon Chen, MSc, AGACNP-BC, CCRN, CPEN
Fidelindo Lim, DNP, CCRN
Published in the Nurse Practitioner Journal, Oct. 2016 Issue
A Variant Case
A 52-year-old non-smoker female with no cardiac history was diagnosed with Hodgkin’s lymphoma where she previously received chemotherapy followed by stem cell transplant. After a period of remission, her lymphoma recurred and she is readmitted to an oncology unit for a second stem cell transplant. Her inpatient post-transplant course was largely uneventful until five days later when she started to complain of crushing sub-sternal, non-radiating chest pain, associated shortness of breath. An electrocardiogram (EKG) done at the time showed normal sinus rhythm with unremarkable findings compared with baseline EKG. Her chest pain was attributed to gastric acid reflux and she was given an antacid (Maalox) for symptom relief.
An hour later, the patient reported worsening chest pain at rest accompanied by shortness of breath and an episode of transient unresponsiveness witnessed by her husband. The registered nurse activated the hospital rapid response system (RRT). Upon arrival of the team, the patient was responding appropriately and complained of persistent “chest pressure” rated at 7/10. The 12-lead EKG this time showed third degree heart block (See Figure 1) with a rate of 57 beats per minute. The patient’s blood pressure was 85/49, respiratory rate 22/minute, afebrile and oxygen saturation of 92% on room air. Transcutaneous pacing pads were applied and the patient was maintained on 2 L/minute nasal cannula oxygen (no drugs given since none was indicated at the time). Serial EKGs were done and a cardiology consult was requested.
Subsequent EKG revealed normal sinus rhythm, with a heart rate of 74 and ST depression (approximately 2 mm) in leads I, aVL and V2 (See Figure 2). A succeeding EKG revealed deepened ST depression in leads I, aVL, and V2 along with ST elevation in the inferior leads (See Figure 3). An STEMI alert was activated and she was promptly transferred to an outside institution equipped with a cardiac catheterization lab.
The patient’s initial troponin was negative. Her left heart catheterization showed a 20% stenosis of the right coronary artery, and a 20% stenosis of the left anterior descending artery (Done upon transfer to Cornell). However, during the left ventricular scan, the patient became hypotensive, and her EKG exhibited a complete heart block and inferior wall ischemia. The patient was re-catheterized which showed 80-90% occlusion of the right coronary artery. She was given intra-arterial nitroglycerin, after which symptoms significantly improved. Her symptoms, along with EKG and catheterization findings are consistent with variant angina, also known as Prinzmetal’s angina.
What’s Happening Here? Pathophysiology of Prinzmetal Angina
Prinzmetal angina was first described in the 1950s and was thought to be a distinct type of angina pectoris since it typically presents during rest and is not associated with exertion (1). The condition is also referred to as variant angina, Prinzmetal's variant angina and angina inversa. The cause was attributed the temporary occlusion of coronary vessels due to increased vascular tone (1). Subsequent studies confirmed that the mechanism of this disease is due to coronary vasospasms (2). This process is different from the occlusive changes caused by atherosclerotic coronary artery disease (4). The phenomenon occurs in approximately 2-10% of patients of the General population (3). Although the exact pathogenesis of this condition is still being debated, it is believed that endothelial dysfunction, inappropriate nitric oxide release, and calcium channel disorders are all potential causes (2). Typical symptoms include retro-sternal chest pain that occurs at rest and there appears to be a circadian pattern, with patients’ typically experiencing chest pain early in the morning. EKG changes may show transient ST elevations in severe cases (4). Troponin (normal range is less than 0.04 ng/mL) is mostly negative and coronary catheterization often shows non-occlusive coronary arteries with vasospasm (4). Traditionally, patients are treated with nitroglycerin and calcium channel blockers with great success (4). Complications of Prinzmetal angina can include dysrhythmia, heart blocks, and even cardiac arrest (5-9).
Current Best Practices
At present there are no established guidelines in North America or Europe for the diagnosis and treatment of Prinzmetal angina due to its decreasing incidence (12) primarily attributed to the widespread availability and use of calcium channel blockers in the treatment of hypertension and other conditions (12). However, in Japan, where the incidence is three times higher compared to the United States, a practice guideline has been issued (12). Diagnosis of Prinzmetal angina is made based on the combination of clinical symptoms and invasive and non-invasive testing (11). Definitive diagnosis is made if characteristic EKG changes are noted during an attack or that vasospasm with stenosis over 90% is noted on angiography (11). A likely diagnosis is made if the symptoms appear at rest, induced by hyperventilation, and is suppressed by calcium channel blockers but not beta blockers (11) (13). No recommendation is made for specific calcium channel blockers. Acute management consists of nitrates with no specific recommendation is made for route, for chest pain relief and calcium channel blocker for long term management (12).
The patient was given Aspirin 325 mg, Clopidogrel 300 mg, 4 mg of Morphine for pain, 1 liter of IV crystalloid for hypotension, and a Heparin drip was initiated at 16 units/kg/hour. Patient was transferred to another facility for cardiac catheterization and further management.
At the time of chest pain, the patient was transferred to another facility for cardiac catheterization and stayed briefly for observation. She was eventually readmitted to her primary facility where continued treatment for her lymphoma. She was discharged home with calcium channel blockers and nitroglycerin and outpatient follow up with a cardiologist.
Clinical and Nursing Implications
Since smoking is strongly correlated with Prinzmetal angina, smoke cessation is key to preventing recurrence of symptoms (2).The case presented here was unique in that the patient has no smoking history. Due to her vasospasm vessel distribution; her symptoms mimicked an inferior infarct with high degree heart block. This case highlights the importance of serial EKGs and if possible, telemetry monitoring for suspected Prinzmetal angina patients. The transient nature of this disease makes it elusive to a onetime 12-lead EKG. It’s important for the clinician to hold a degree of suspicion and obtain serial EKGs if the patient remains symptomatic to offset the development of myocardial infarction.
Patients with Prinzmetal angina can have atypical presentations (e.g., blackouts and urinary incontinence) that mimics other conditions such seizure or epilepsy (4). Vigilant assessment by nurses and other clinicians is essential in ruling out other conditions. Nothing the timing of angina is crucial information to gather during health history interview. Nurses can collaborate with providers to order Holter monitoring for patients with symptoms suggestive of Prinzmetal angina to aid in definitive diagnosis (4). For patients undergoing cardiac catheterization, nurses can provide high-quality patient education using the teach-back method. The patient and their caregivers should be encouraged to ask questions and be referred to reputable sources of online information such as the American Heart Association (13).
Discharge teachings of patients diagnosed with Prinzmetal angina might include instructions related to taking calcium channel blockers and nitrates. Patients are reminded not to take calcium channel blockers with grapefruit juice due to latter’s potential to reduce presystemic clearance of the drugs decreases and subsequent increase in bioavailability that could lead to hypotension (14). To reduce the risk for orthostatic hypotension, patients are reminded to get up slowly from recumbent or sitting position and to encourage them to remain well hydrated. Since one of the most common side effects of nitrates is headache, patient’s need to collaborate with their provider on how best to manage this considering the patient’s taking into consideration potential drug interactions and potential side effects of analgesics.
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