A 74-year-old male patient with a medical history of permanent atrial fibrillation, nonischemic cardiomyopathy (left ventricular ejection fraction [LVEF] of 30%), hypertension, chronic kidney disease, and rib sarcoma s/p chemoradiation presented with fatigue and exertional dyspnea for 6 months. Coronary angiogram showed mild coronary artery disease. Echocardiography showed his calculated aortic valve area (AVA) was 0.9 cm2 (indexed AVA = 0.4 cm2) with peak gradient of 36 mmHg and mean gradient of 22 mmHg (averaged over 5 beats). He was referred for low-dose dobutamine stress echocardiogram, which showed an increase in aortic valve gradients to peak of 69 mmHg and mean of 41 mmHg (averaged over 5 beats) while AVA remained the same at 0.9 cm2. There was also an increase in stroke volume by 30%. The patient was evaluated by a multidisciplinary team and determined to be at intermediate risk for cardiovascular complications from aortic valve surgery.
What intervention would you recommend next?
The correct answer is: A. Transcatheter aortic valve replacement (TAVR)
The patient has dyspnea from his severe aortic stenosis (AS), and patients with symptomatic AS should be referred for intervention. Medical management with repeat echocardiogram is therefore not indicated; delaying intervention will expose him to risk. The dobutamine stress echocardiogram showed an increase in his transaortic gradient while maintaining an AVA <1.0 cm2, thus confirming the diagnosis of severe AS; an aortic valve calcium score is not necessary.
Severe AS can be subclassified into three groups based on the aortic valve gradient:
Low-flow/low-gradient AS with normal LVEF
Low-flow/low-gradient AS with depressed LVEF (i.e., classic low-flow/low-gradient AS)1
Patients with classic low-flow/low-gradient AS will have calcified aortic valve leaflets, LVEF <50%, AVA <1.0 cm2, Vmax <4 m/sec, and an indexed stroke volume of <35 mL/m2 on echocardiogram. A low indexed stroke volume may account for the low aortic valve gradient by Doppler echocardiography. Low-dose dobutamine stress echocardiogram can be performed in patients with reduced LVEF in an attempt to increase the left ventricular contractility and forward flow to differentiate true classic low-flow/low-gradient AS from pseudostenosis. A recent study showed that after TAVR procedure, LVEF improved despite the presence or absence of contractile reserve.2
For patients with significant valvular heart disease for whom intervention is being considered, evaluation of the patient's anatomy and procedural risk by a multidisciplinary heart team is recommended. Initially, TAVR was indicated for "inoperable" or "extreme risk" patients,3,4 and later TAVR was considered non-inferior to surgery in "intermediate risk" patients.5,6 Most recently, US Food and Drug Administration approval was obtained for TAVR in low surgical risk patients. In our case, the patient was found to be at intermediate surgical risk and referred for TAVR procedure.
Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2017;135:e1159-e1195.
Maes F, Lerakis S, Barbosa Ribeiro H, et al. Outcomes From Transcatheter Aortic Valve Replacement in Patients With Low-Flow, Low-Gradient Aortic Stenosis and Left Ventricular Ejection Fraction Less Than 30%: A Substudy From the TOPAS-TAVI Registry. JAMA Cardiol 2019;4:64-70.
Leon MB, Smith CR, Mack M, et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med 2010;363:1597-1607.
Popma JJ, Adams DH, Reardon MJ, et al. Transcatheter aortic valve replacement using a self-expanding bioprosthesis in patients with severe aortic stenosis at extreme risk for surgery. J Am Coll Cardiol 2014;63:1972-81.
Leon MB, Smith CR, Mack MJ, et al. Transcatheter or Surgical Aortic-Valve Replacement in Intermediate-Risk Patients. N Engl J Med 2016;374:1609-20.
Reardon MJ, Van Mieghem NM, Popma JJ, et al. Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients. N Engl J Med 2017;376:1321-31.