Is my patient with aortic stenosis and no atrial fibrillation at higher risk of a cerebrovascular accident?

Several lines of evidence suggests that even in the absence of atrial fibrillation, patients with aortic stenosis (AS) may be at higher risk of a cerebrovascular accident (CVA).

A population-based study from Mayo Clinic examining the risk of cerebrovascular events (primarliy ischemic strokes or transient ischemic attacks) among patients with valvular heart disease reported severe aortic stenosis (study defined as mean pressure gradient >30 mm Hg) as a predictor of cerebrovascular event, independent from atrial fibrillation or age and at rates similar to those of mitral stenosis 1.  Similarly, the simvastatin and ezetimibe in AS study involving patients with mild-to-moderate AS not prescribed oral anticoagulation found that CHA2DS2-VASc was a major predictor of stroke, independent of atrial fibrillation or aortic valve replacement2. Thromboembolic CVA has also been reported in the setting of calcified bicuspid aortic valve with moderate-severe AS3.

Potential factors increasing the risk of CVA in AS include calcium embolization from the valve and increased microthrombus formation on the valve which may be present in 53% of stenotic aortic valves3,4.  In addition, severe AS may be a marker for other conditions that increase risk of CVA, such as atherosclerosis or prothrombotic tendencies1.

References

  1. Petty GW, Khandheria BK, Whisant JP. Predictors of cerebrovascular event and death among patients with valvular heart disease: A population-based study. Stroke 2000;31:2628-2635. http://stroke.ahajournals.org/content/strokeaha/31/11/2628.full.pdf
  2. Greve AM, Dalsgaard M, Bang CN, et al. Stroke in patients with aortic stenosis: The simvastatin and ezetimibe in aortic stenosis study. Stroke 2014;45:1939-1946. http://stroke.ahajournals.org/content/strokeaha/45/7/1939.full.pdf
  3. Mahajan N, Khetarpal V, Alfonso L. Stroke secondary to calcific bicuspid aortic valve: Case report and literature review. J Cardiol 2009;54:158-61. https://www.ncbi.nlm.nih.gov/pubmed/19632538
  4. Pleet AB, Massey EW, Vengrow ME. TIA, stroke, and the bicuspid aortic valve. Neurology 1981;31:1540-2. https://www.ncbi.nlm.nih.gov/pubmed/7198207 
Is my patient with aortic stenosis and no atrial fibrillation at higher risk of a cerebrovascular accident?

My patient with atrial fibrillation (AF) with a CHA2DS2-VASc score ≥2 is not a candidate for anticoagulation due to excessive bleeding risk. Does high-dose aspirin provide an effective alternative for stroke prevention in this setting?

 The SPAF (Stroke Prevention in Atrial Fibrillation) trial1 found a 42% reduction in overall risk of stroke with daily aspirin (325 mg). However, critics note that no benefit was observed among patients > 75 y or those with severe stroke.

7 other studies on the topic failed to confirm reduction in the risk of stroke at a range of aspirin doses (25mg bid-1,300mg qd) 2. These studies reported that aspirin is associated with a 19% reduction in stroke incidence (similar to patients with vascular disease), with a 95% CI that crosses zero (-1% to 35%), raising doubts about its actual benefit in AF3. For secondary prevention, aspirin was associated with a 2.5% reduction in the annual risk of stroke. However, these results were influenced by the only trial with a favorable outcome, SPAF-14.

In short, even at higher doses, aspirin may not be the answer for stroke prevention in patients with AF.

 References

  1. Stroke Prevention in Atrial Fibrillation Study. Final results. Circulation 1991;84, 527–39.
  2. January CT, Wann LS, Alpert  JS, et al. 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation  2014;130, e199–e267.
  3. European Heart Rhythm Association et al. Guidelines for the management of atrial fibrillation: the Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Europace  2010; 12, 1360–420.
  4. Sabir IN, Matthews GDK,  Huang, CL-H. Antithrombotic therapy in atrial fibrillation: aspirin is rarely the right choice. Postgrad Med J 2013; 89, 346–51.

 

Contributed by Jacqueline Boehme, M.D., Medical Resident, Mass General Hospital

My patient with atrial fibrillation (AF) with a CHA2DS2-VASc score ≥2 is not a candidate for anticoagulation due to excessive bleeding risk. Does high-dose aspirin provide an effective alternative for stroke prevention in this setting?

Does marijuana use lead to any adverse cardiovascular effects?

Although marijuana is often not considered to have serious cardiovascular effects, in animal studies THC, the active ingredient in cannabis, has been found to affect cardiovascular activity through a number of mechanisms, including inhibition of adrenal catecholamine secretion and modulation of cardiac vagal tone through inhibition of norepinephrine release from sympathetic neurons (1).

There have also been reports of temporal association between marijuana use and acute coronary syndrome, cardiac arrhythmias, cerebrovascular events, including TIA’s, strokes, and cerebral vasospasm, as well as peripheral vascular events, including arteritis, Raynaud’s phenomenon, and digital necrosis (2).

In a recent comprehensive case series, about 2.0 % of all cannabis-associated adverse events were reported cardiovascular in nature, with 25% resulting in death (2). However, it is often difficult to determine the relative contribution of marijuana and other concurrent conditions or substances (e.g. alcohol and tobacco) when cardiovascular complications occur. More research in this area is needed.

References

1. Szabo B, Nordheim U, Niederhoffer N. Effects of cannabinoids on sympathetic and parasympathetic neuroeffector transmission in the rabbit heart. J Pharmacol ExpTher 2001; 297:819-826. http://jpet.aspetjournals.org/content/297/2/819

2. Jouanjus E, Lapeyre-Mestre M, Micallef J, et al. Cannabis use: signal of increasing risk of serious cardiovascular disorders. J Am Heart Assoc 2014; 3:e000638.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187498/

Contributed by Pierre Ankomah, MD, Boston, MA

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Does marijuana use lead to any adverse cardiovascular effects?