Hemodynamic Assessment of Severe Aortic Stenosis via Transradial Approach is Safe

Abstract: Background. Patients with a discrepancy between clinical presentation and echocardiographic severity of aortic stenosis require invasive hemodynamic assessment. The comparative safety and feasibility of transradial cardiac catheterization in comparison with the traditional transfemoral approach in this usually complex subset of patients is not known. We sought to evaluate the safety, feasibility, and time to cross severely stenosed aortic valves via radial approach. Methods. All patients who were successfully assessed for aortic stenosis with a dual-lumen catheter and found to have severe aortic stenosis (calculated aortic valve area <1.0 cm²) in the last 2 years at our institution were retrospectively evaluated. Demographic, clinical, and procedural data were compared between the TF group (femoral arterial and venous access) and TR group (radial artery and basilic or cephalic vein access). Results. A total of 176 patients underwent left and right heart catheterization using femoral access, while 58 patients had their procedures performed via radial artery and arm vein access. Fluoroscopy time was comparable between TR and TF groups (14.97 ± 4.6 minutes vs 12.90 ± 3.9 minutes, respectively; P=.23), as was the time to cross the aortic valve (132 ± 209 seconds vs 128 ± 226 seconds, respectively; P=.39). Incidence of cerebrovascular events was not different between the two groups (2.3% vs 1.75%, respectively; P=.14). Access-site complications were significantly higher in the TF group vs the TR group (5.11% vs 0%, respectively; P<.01).  Conclusion. Transradial retrograde crossing of severely stenosed aortic valve is feasible using ordinary equipment, with reduced access-site related complications.  

J INVASIVE CARDIOL 2015;27(12):E308-E311

Key words: transradial catheterization, retrograde crossing of aortic valve, aortic stenosis evaluation

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Coronary angiography is recommended before aortic valve replacement (AVR) in patients with aortic stenosis (AS) at risk for coronary artery disease (CAD) (recommendation class I: level of evidence B). A complete left and right heart catheterization may be necessary to assess the hemodynamic severity of the AS if there is a discrepancy between clinical and echocardiographic data (recommendation class I: level of evidence C). Similarly, invasive hemodynamic measurements with infusion of dobutamine can be useful for evaluation of patients with low-flow/low-gradient AS and left ventricular (LV) dysfunction (recommendation class IIA: level of evidence C).^1,2 A complete assessment of AS requires measurement of transvalvular flow and mean transvalvular pressure gradient, as well as calculation of the effective valve area. The ideal method to evaluate the transvalvular gradient is by using a dual-lumen catheter and recording a simultaneous pressure tracing from the aorta (AO) and LV. Retrograde crossing of the aortic valve in the presence of AS is associated with 3% clinical stroke risk and 22% silent cerebral embolic events.³ The most important independent predictor of silent cerebral infarction was the time required for crossing the aortic valve.⁴ We sought to evaluate the safety, feasibility, and time to cross severely stenosed aortic valve via radial approach.

Methods 

We retrospectively reviewed the records of patients undergoing cardiac catheterization to evaluate AS at our institution between December 2010 and April 2013. The database was queried for: (1) use of a dual-lumen Langston’s catheter to simultaneously record LV and AO pressures; (2) right and left heart catheterization performed during the index procedure; and (3) calculated aortic valve area (AVA) <1.0 cm² by Hakki’s formula. Out of the 258 patients meeting the inclusion criteria, 14 patients were excluded from the evaluation because of either: (1) incomplete data recorded at the time of procedure; or (2) failure to record simultaneous LV/AO pressures. The patients were divided into the transfemoral (TF) group (femoral artery and femoral vein access) or the transradial (TR) group (radial artery and basilic vein or cephalic vein access). Out of the remaining 244 patients, 8 were excluded because radial artery and femoral vein access were used and 2 patients were excluded because basilic vein and femoral artery were used. Demographic, clinical, and procedural data were compared between TF and TR groups for the resulting study group of 234 patients. Fourteen of the 234 patients required dobutamine drip to evaluate the low-flow, low-gradient AS. 

TR group. A 6 Fr hydrophilic sheath was placed in the radial artery using a posterior-wall puncture technique.⁵ The basilic or cephalic superficial vein access was achieved with a 5 Fr sheath.⁶ A 5 Fr balloon-tipped catheter (Arrow International) was used to perform the right heart catheterization. After completing diagnostic coronary angiography, a Judkin’s right (JR) 4 catheter and a straight-tip 0.035˝ metallic (non-hydrophilic) wire was used to cross the stenosed aortic valve. If unsuccessful, a Brachial 1, Amplatz right (AR) 1, or Amplatz left (AL) 1 catheter was used to cross the aortic valve with a straight-tipped wire. After crossing the valve, the catheter was advanced into the LV. Subsequently, using a 260 cm J-tip support wire, the catheter was exchanged for a Langston dual-lumen pigtail catheter. Simultaneous pressure measurement and LV angiography were performed when renal function allowed using an additional 30 cc of contrast. The AV gradient, arterial oxygen saturation, mixed venous oxygen saturation, cardiac output by Fick’s method, and AVA using Hakki’s formula were recorded.

TF group. A 6 Fr sheath was placed in the femoral artery. A 7 Fr sheath was placed in the femoral vein in all but 2 cases where a 5 Fr sheath was placed in the femoral vein.  All femoral artery and vein access procedures were guided by palpation and fluoroscopic guidance. A balloon-tipped catheter (7 Fr or 5 Fr) was used to perform right heart catheterization in a standard fashion. After completing diagnostic coronary angiography, a 6 Fr catheter (operator’s choice) along with a straight-tip 0.035˝ metallic guidewire was used to cross the valve. Most commonly used catheters were Brachial 1, AL1, and AL2. After crossing the valve successfully, the catheter used to cross the valve was exchanged for a Langston dual-lumen pigtail catheter and simultaneous pressures were measured from the LV and AO. Similar to the TR group, the AV gradient, arterial oxygen saturation, mixed venous oxygen saturation, cardiac output by Fick’s method, and AVA using Hakki’s formula were recorded. 

Valve crossing time. As a standard operating procedure in our cath lab, a timer is turned on with the first attempt to advance the wire out of the catheter to cross the AV. The timer is turned off as the catheter is advanced into the LV.  This time duration was defined as time to cross the AV.

Statistical analysis. Categorical variables are presented as counts and percentages. Continuous variables following a normal distribution are presented with a mean value and compared using Student’s t-test. Data were processed using SPSS version 14 (SPSS, Inc). All tests were two-sided and a P-value <.05 was considered statistically significant. 

Results

Out of the 234 patients included in this cross-sectional analysis, a total of 176 had their left and right heart catheterization performed through femoral artery and femoral vein access, while 58 had their procedures performed via radial artery and arm vein access (Table 1). Clinical characteristics, including the severity of the aortic stenosis, were comparable between the two groups (Table 1). The TR group trended toward requiring fewer catheter exchanges to cross the severely stenosed aortic valves compared with the TF group. This may be explained by one operator performing the majority of the radial cases, whereas three different operators performed the cases in the TF group. A JR 4 catheter was most likely used from the radial approach and a brachial 1 catheter was most likely used from the femoral approach to cross the valve. No significant difference was observed in fluoroscopy time (14.97 ± 4.6 minutes vs 12.9 ± 3.9 minutes; P=.23) or the time to cross the aortic valve between the TR and TF groups (132 ± 209 seconds vs 128 ± 226 seconds; P=.39), respectively. The incidence of cerebrovascular events was not different between the two groups (2.3% in the TF group vs 1.75% in the TR group; P=.14). Four patients in the TF group suffered a clinical transient ischemic attack (TIA). Two of the patients had postprocedure transient visual changes, 1 patient had dysarthria, and 1 patient had left facial droop. All 4 patients recovered from their neurological symptoms without any residual deficit. One patient in the TR group suffered a cerebrovascular accident (CVA) with a partially residual hemi-sensory loss in their right-upper extremity. All 5 patients were investigated with magnetic resonance imaging and treated conservatively as per neurology and neurosurgery consultations. Access-site complications were significantly higher in the TF group compared with the TR group (5.11% vs 0%, respectively; P<.01) (Figure 1). In the TF group, 5 female and 2 male patients suffered from either type-2 or type-3 bleeding as defined by the Bleeding Academic Research Consortium criteria.⁷ Two of these female patients required blood transfusion. Two patients (1 male and 1 female) developed a pseudoaneurysm. None of the patients from either group suffered from type-5 bleeding.⁷

Discussion

Radial access has been shown to have fewer access-site complications when compared with femoral and brachial access.⁸ Due to the safety associated with radial access, the European Society of Cardiology consensus statement recently recommended that radial access should be the default approach for cardiac catheterization.⁹ Elderly patients,¹⁰ particularly females,¹¹ are at the highest risk for vascular access complications. 

Elderly patients with AS also have a high prevalence of tortuosity and remodeled anatomy in the subclavian and brachiocephalic region.¹² This can make retrograde crossing of the aortic valve using transradial access technically difficult, likely requiring more attempts and longer time to cross the aortic valve.  This may increase the risk of cerebrovascular events, since the time required for crossing the aortic valve has been found to be the most important independent predictor of silent cerebral infarction.⁴ These attributes frequently discourage the operator from choosing TR access for cardiac catheterization in patients with severe AS. 

In our unselected cohort of patients with severe AS (mean gradient, 44 mm Hg in the TF group and 48 mm Hg in the TR group), we found no significant difference in the time required to cross the aortic valve between the two groups, implying equivalent safety in regard to embolic neurologic events. Operator experience is an important predictor of cerebrovascular insult while crossing a stenosed aortic valve.⁴ The operator experience in both groups was comparable with all four interventional cardiologists (one radial, three femoral operators). Access-site complications were observed significantly more frequently in the TF group compared with the TR group. Elderly patients typically suffering from degenerative AS are at the highest risk for vascular access complications.⁹ The virtual absence of access-site complications in the TR cohort makes TR access an attractive alternative for this subset of patients.     

The ideal invasive method to evaluate the transvalvular gradient is by simultaneous recording of aortic and LV pressure tracings using a 6 Fr dual-lumen catheter. Many elderly female patients with small radial arteries may not allow easy insertion of a 6 Fr sheath. As the outer diameter (OD) of a 6 Fr catheter is 2.0 mm, while the OD of a 6 Fr hydrophilic glide sheath (Terumo Corporation) is 2.61 mm, we insert only 1 cm of the sheath into the radial artery. Using this method, a 6 Fr catheter can be used with an atraumatic entry and without expanding or irritating a small radial artery (Figure 2). 

Omran et al³ reported that 3 of 101 patients randomly assigned to retrograde crossing of severely stenosed AV suffered from clinically apparent neurological deficit. All procedures in their study were performed via femoral approach and using 6 Fr or 7 Fr catheters. In our more contemporary analysis, we noted transient ischemic attack/cerebrovascular accident rates of 2.3% in the TF group and 1.75% in the TR group, suggesting that retrograde crossing of the AV should be reserved for only the indications discussed earlier. 

Our study underscores the fact that while adopting transradial access for a variety of clinical subsets of patients undergoing invasive cardiovascular procedures, including those with severe AS, the same transfemoral hardware can be used. Although we did not encounter any adverse hemodynamic consequences from the administration of a vasodilator cocktail, clinical judgment should be used, because vasodilation could be destabilizing in patients with critical AS. 

Study limitations. This study is associated with the bias inherent in a retrospective cross-sectional review from a single center. We only included patients with successful use of a 6 Fr Langston catheter, and so this study cannot comment on the success rate of radial access vs femoral access to cross severely stenosed aortic valves. We routinely used 50 U/kg unfractionated heparin administered intravenously for all transradial procedures and practiced patent hemostasis for postprocedure care, but did not routinely evaluate radial artery patency in all patients. Therefore, we could not report the incidence of asymptomatic radial artery occlusion.

Conclusion

Transradial retrograde crossing of severely stenosed aortic valve has comparable feasibility to transfemoral approach for experienced operators using usual equipment, as well as a possibility of lower incidence of access-related complications. 

References

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7.    Mehran R, Rao SV, Bhatt DL, et al. Standardized bleeding definitions for cardiovascular clinical trials: a consensus report from the Bleeding Academic Research Consortium. Circulation. 2011;123:2736-2747.

8.    Kiemeneij F, Laarman G, Odekerken D, et al. Randomized comparison of percutaneous transluminal coronary angioplasty by the radial, brachial and femoral approaches: the ACCESS study. J Am Coll Cardiol. 1997;29:1269-1275. 

9.    Hamon M, Pristipino C, Di Mario C, et al. Consensus document on the radial approach in percutaneous cardiovascular interventions: position paper by the European Association of Percutaneous Cardiovascular Interventions and Working Groups on Acute Cardiac Care^** and Thrombosis of the European Society of Cardiology. EuroIntervention. 2013;8:1242-1251.

10.    Sherev D, Shaw RE, Brent B. Angiographic predictors of femoral access site complications: implication for planned percutaneous coronary intervention. Catheter Cardiovasc Interv. 2005;65:196-202. 

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From the ¹Transradial Program, Deborah Heart & Lung Institute, Browns Mills, New Jersey; ²Cardiology Fellowship Program, The Commonwealth Medical College, Scranton, Pennsylvania; and ³Cardiology Department, NHL Municipal Medical College, Ahmedabad, India.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Pancholy reports speaker fees from Medtronic and Terumo Corporation. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted February 6, 2015, provisional acceptance given February 10, 2015, final version accepted February 16, 2015.

Address for correspondence: Kintur Sanghvi, MD, Deborah Heart & Lung Center, 200 Trenton Road, Browns Mills, NJ 08015. Email: sanghvik@deborah.org