Case Study: Vascular Risk Factors Reach Tipping Point

Case History: A 45-year-old Hispanic male with diabetes, hypertension, obesity, obstructive sleep apnea, and occasional cigarette use complained of sudden onset of slurred speech and weakness in the right arm and right leg that began two days before admission. By the time he was examined in the emergency department (ED), his symptoms had completely resolved.

Physical Examination: An obese male in no acute distress with elevated blood pressure of 189/122 mmHg, pulse of 122 bpm, and weight of 352 lbs. The rest of his physical and neurological examinations were normal.

Laboratories: Complete blood count and chemistry panel were normal. Diabetes was poorly controlled with a random glucose of 272 (70 to 110 mg/dl) and HbA1C of 10.3 (4.3% to 6.1%). Total cholesterol was elevated at 250 (140 mg to 200 mg/dl) with an LDL of 168 (0 mg to 99 mg/dl), but normal HDL of 59 (35 mg to 85 mg/dl) and normal triglycerides of 119 (30 mg to 175 mg/dl). Blood alcohol level was elevated at 0.07 nmg/dl, just below the legal limit of intoxication (0.08 nmg/dl).

Initial CT brain was normal (Figure 1). Magnetic resonance diffusion weighted imaging (DWI) of the brain revealed bright foci of restricted diffusion in the left pons (Figure 2). Bright foci of restricted diffusion in the left pons were dark on apparent diffusion coefficient (ADC) (Figure 3), suggesting acute brainstem infarction. Magnetic resonance angiography (MRA) revealed focal high-grade stenosis of the proximal basilar artery with reconstitution of flow in the distal basilar artery.

Figure 1: Initial CT brain was normal.

Figure 2: Magnetic resonance diffusion weighted imaging (DWI) of the brain revealed bright foci of restricted diffusion in the left pons

Figure 3: Bright foci of restricted diffusion in the left pons were dark on apparent diffusion coefficient (ADC), suggesting acute brainstem infarction

Figure 4: Magnetic resonance angiography (MRA) revealed focal high-grade stenosis of the proximal basilar artery with reconstitution of flow in the distal basilar artery

Severe stenosis of the proximal basilar artery was the probable etiology of ischemic brainstem stroke. This patient had multiple risk factors for ischemic vascular disease including cigarette smoking, diabetes, elevated cholesterol, hypertension and obesity. His symptoms of right-sided weakness were consistent with the acute ischemic lesions in his left pons observed on MRI.  He was not treated with tissue plasminogen activator (tPA) because he presented outside the 3-hour time window and his symptoms had spontaneously resolved, leaving him with an National Institutes of Health (NIH) stroke score of zero. Magnetic resonance angiography confirmed severe stenosis of the proximal basilar artery as the probable etiology of his ischemic brainstem stroke.

Of the approximately 900,000 strokes and transient ischemic attacks (TIAs) in the US annually, 70,000 to 90,000 are caused by intracranial arterial stenosis.[1] The risk of recurrent stroke in these patients can be as high as 15% per year, even in those medically treated with aspirin and risk factor management. African Americans, Asians, and Hispanics are at particular risk for stroke due to intracranial artery stenosis.

Although anticoagulation had previously been utilized to treat intracranial arterial stenosis, a large randomized study revealed that warfarin had no benefit over aspirin and had higher adverse events.[1] Accordingly, antiplatelet agents are now recommended instead of anticoagulation. While percutaneous transluminal angioplasty might appear to be an attractive option to treat symptomatic intracranial arterial stenosis, it has not proved superior to aggressive medical therapy.[2] In fact, two randomized multicenter clinical trials (SAMMPRIS[3] and VISSIT[4]) revealed an increased risk of stroke in the angioplasty groups.

This patient was prescribed aggressive medical therapy. In addition, he was encouraged to embrace a healthy lifestyle, including exercise, reduction in alcohol intake, smoking cessation, and weight loss in the hope of preventing a subsequent stroke.