Background: Invasive hemodynamic assessment still remains of great importance in the evaluation of patients with aortic stenosis. We tested the feasibility of using the Navvus Rapid Exchange FFR microcatheter to obtain simultaneous left ventricular (LV) and aortic pressure with single arterial access in the absence of a dual lumen pigtail catheter. Case Summary: We present three cases of aortic stenosis of variable severity on transthoracic echocardiogram, referred for hemodynamic evaluation for accurate diagnosis and the next step in management. Because of the recall of the Langston dual lumen pigtail catheter, we utilized the Navvus microcatheter to measure the LV pressure and the guide catheter to measure the aortic pressure simultaneously, with single arterial access for accurate mean aortic valve gradient calculation to assess the severity of aortic stenosis. Discussion: The Navvus microcatheter can be utilized in the evaluation of aortic stenosis with single arterial access in the absence of a dual lumen pigtail catheter.
Invasive hemodynamic assessment still remains of great importance in the evaluation of patients with aortic stenosis. Optimal hemodynamic evaluation of aortic stenosis is extremely important when patients are referred for diagnosis of the severity of an aortic stenosis. For this type of hemodynamic assessment, it is recommended that the mean aortic valve gradient be used, which is the integrated gradient throughout the entire systolic ejection period and the optimal indicator of severity of obstruction.1 Simultaneous left ventricle and aortic pressure measurements have been described as the standard for the evaluation of the mean gradient across the aortic valve.1,2 This is usually performed using the Langston (Vascular Solutions) dual lumen pigtail catheter or by obtaining dual arterial accesses. With the recall of the Langston dual lumen pigtail catheter, dual arterial accesses are becoming increasingly routine for aortic valve gradient evaluation.
The feasibility of single arterial access for simultaneous LV and aortic pressure measurement using a fractional flow reserve (FFR) pressure wire has been described, but not as a routine practice.3 We utilized single arterial access to perform simultaneous LV and aortic pressure measurement with the Navvus Rapid Exchange Fractional Flow Reserve (FFR) MicroCatheter (ACIST Medical Systems).2 In the case series presented below, we obtain right femoral or radial arterial access with ultrasound guidance and utilize an Amplatz Left (AL) 1 guide catheter. We cross the aortic valve with a straight tip .035-inch wire and advance the AL1 guide catheter over the wire into the left ventricle. The 0.035 wire is removed and the Navvus microcatheter advanced into the tip of AL1 guide catheter in the left ventricle. We make sure that both the guide catheter and Navvus microcatheter are appropriately rebalanced to zero prior to equalizing. Once this microcatheter is at the tip of the guide catheter, we equalize the pressures, then pull the guide catheter into the ascending aorta, leaving the microcatheter in the LV for simultaneous LV pressure measurement from the Navvus microcatheter and aortic pressure measurement from the guide catheter. In the case series below, we were able to successfully utilize this approach and accurately measure the gradient across the aortic valve.
Patient 1. This was a patient with known history of coronary artery disease (CAD), coronary artery bypass graft (CABG) surgery, and bioprosthetic aortic valve replacement. Transthoracic echocardiogram demonstrated evidence of an aortic stenosis with a mean gradient of 33 mmHg and a valve area of 0.85 cm2. He was referred for a right and left heart catheterization for further evaluation of his aortic stenosis, based on his progressive dyspnea. He underwent simultaneous LV and aortic pressure measurement for gradient calculation across the aortic valve with guide catheter in the aorta and the Navvus microcatheter in the left ventricle (Figures 1-3).
Patient 2. This was a patient with history of CAD, percutaneous coronary intervention (PCI), and aortic stenosis. He had been experiencing worsening fatigue in the recent past. Transthoracic echocardiogram demonstrated an ejection fraction (EF) around 45-50%, a mean gradient of 26 mmHg across the aortic valve, and an indexed valve area of 0.4 cm2. He was referred for right and left heart catheterization for further evaluation of his aortic stenosis. He underwent simultaneous LV and aortic pressure measurement for gradient calculation across the aortic valve with a guide catheter in the aorta and the Navvus microcatheter in the left ventricle (Figures 4-6).
Patient 3. This was a patient with history of hypertension who presented with fatigue and shortness of breath. She was noted to have acute congestive heart failure symptoms. Her transthoracic echocardiogram demonstrated normal LV systolic function with an EF of around 65-70%, with a mean gradient of 20 mmHg and a valve area of 0.9 cm2. She was referred for a hemodynamic evaluation of aortic stenosis severity. She underwent simultaneous LV and aortic pressure measurement for gradient calculation across the aortic valve with guide catheter in the aorta and the Navvus microcatheter in the left ventricle.
For the accurate diagnosis of severity of aortic stenosis using hemodynamic evaluation, simultaneous left ventricular and ascending aortic pressure measurement has been the gold standard. Use of a dual lumen pigtail catheter or dual arterial accesses remain the standard options for simultaneous LV and aortic pressure measurement. Because of the recall of the Langston catheter, most cardiac catheterization laboratories are performing the dual arterial accesses that can provide simultaneous LV and aortic pressures for accurate aortic valve gradient. However, dual arterial accesses can be associated with access-related complications. Therefore, we performed simultaneous pressure measurements with single arterial access using the Navvus microcatheter system. A regular pressure wire could be used instead of the Navvus microcatheter, but in working with an .014-inch wire, we encountered artifacts due to wire movement and pressure readings can be artifactual. There is a cost increase of a few hundred dollars per case with the use of our technique; however, in our lab, we have reserved its use for those cases with discrepancies between the clinical and echocardiography findings.
Invasive hemodynamic evaluation of severity of aortic stenosis using the Navvus microcatheter system or a pressure wire remains a feasible alternative for accurate measurement of gradient across the aortic valve with single arterial access. This approach also obviates the need for dual arterial access for accurate gradient measurement across the aortic valve. In the absence of a dual lumen pigtail catheter, this method is a positive alternative for the evaluation of aortic stenosis severity via a single arterial access.
Disclosure: The authors report no conflicts of interest regarding the content herein.
The authors can be contacted via Kasaiah Makam, MD, at email@example.com
- Nishimura RA, Carabello BA. Hemodynamics in the cardiac catheterization laboratory of the 21st century. Circulation. 2012 May 1; 125(17): 2138-2150.
- Folland ED, Parisi AF, Carbone C. Is peripheral arterial pressure a satisfactory substitute for ascending aortic pressure when measuring aortic valve gradients? J Am Coll Cardiol. 1984 Dec; 4(6): 1207-1212.
- Bae JH, Lerman A, Yang E, Rihal C. Feasibility of a pressure wire and single arterial puncture for assessing aortic valve area in patients with aortic stenosis. J Invasive Cardiol. 2006 Aug; 18(8): 359-362.