Safety and Feasibility of Rotational Atherectomy in Elderly Patients With Severe Aortic Stenosis

Abstract: Background. Percutaneous coronary intervention (PCI) followed by transcatheter aortic valve replacement (TAVR) is an alternative to surgery in patients with severe aortic stenosis (AS) and coronary artery disease (CAD). In many, the coronary arteries are severely calcified and best treated with rotational atherectomy (RA). However, RA is not routinely performed in severe AS patients due to safety concerns. There is a paucity of data on the safety of RA in severe AS patients with calcific CAD. Methods. We retrospectively analyzed the medical records of 29 patients with severe AS who underwent elective RA-facilitated PCI at our center between January 1, 2011 and December 31, 2015. Results. Twenty-nine patients (mean age, 79.8 ± 8.8 years) were enrolled. Mean aortic valve area was 0.71 ± 0.20 cm², mean aortic valve gradient was 40.32 ± 9.88 mm Hg. All PCIs were successful (mean diameter stenosis, 86.3 ± 7.6%; mean burr size, 1.62 ± 0.19 mm). Nineteen patients (65.5%) required temporary pacemaker. Eight patients (27.6%) required vasopressors during PCI. There was a significant reduction in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) during RA, but without clinical events. No procedure was aborted and there were no deaths or clinical myocardial infarctions. Conclusion. RA-facilitated PCI can be safely performed in elderly patients with severe AS and severely calcified CAD with low risk of complications. There was a significant but transient drop in SBP, DBP, MAP, and HR during RA. However, this was not associated with clinically significant adverse events. 

J INVASIVE CARDIOL 2017;29(8):271-275.

Key words: aortic stenosis, TAVR, PCI

Aortic stenosis (AS) is the most common form of valvular heart disease in the elderly. AS occurs frequently in conjunction with coronary artery disease (CAD).^1,2 Historically, the standard of care for patients with calcific AS and CAD has been simultaneous surgical aortic valve replacement (SAVR) and coronary artery bypass grafting (CABG).¹ In recent years, transcatheter aortic valve replacement (TAVR) with percutaneous coronary intervention (PCI) has become a safe and reliable option for elderly patients with AS who are at high or intermediate risk from SAVR.^3-5 Significant minorities of these patients (about 30%) have occlusive CAD and undergo PCI prior to undergoing the TAVR procedure.⁶ Since this is an elderly population, many have complex CAD with severely calcified lesions. Although data are sparse, many of these patients are not considered for TAVR due to complex CAD or are incompletely revascularized with PCI prior to TAVR. Rotational atherectomy (RA) is an established modality for percutaneous treatment of calcific CAD with a long history of documented safety and efficacy.^7-10 However, due to safety concerns (hemodynamic instability), RA is not routinely used in patients with severe AS. There is a paucity of information in the published literature about its safety in severe calcific AS. 

The aim of this study was to assess the safety and feasibility of coronary RA in elderly patients with CAD and severe AS under consideration for a TAVR procedure. 

Methods

This is a retrospective, single-center study conducted at an academic tertiary-care center in the United States. We included all cases that underwent RA and had confirmed severe AS between January 1, 2011 and December 31, 2015.

The institutional review board and the human subjects committee approved the study. A detailed manual review of the electronic medical records was then performed on these subjects to collect the demographic, laboratory, echocardiographic, and clinical data. The study investigators also manually reviewed the intraprocedural angiograms and intraprocedural hemodynamic data to collect the needed information. Severity of AS was confirmed with use of Doppler echocardiography and/or direct invasive measurements.

We included all patients who had severe AS (per American College of Cardiology criterion) and who underwent coronary RA within the stated time frame.¹¹ All procedures were performed using the Rotablator RA System (Boston Scientific) using standard techniques at the discretion of the treating cardiologist. Rotablator, Rotalink, and Rotaglide, are registered trademarks of Boston Scientific Corporation. A detailed description of the system can be found in the Boston Scientific Corporation Rotablator reference guide. All patients had liberal use of Rotaglide lubricant per standard protocol during the procedure; in addition, intracoronary nicardipine and nitroglycerin were frequently used prior to and in between burr runs. The Rotaglide cocktail in our laboratory is constituted with 1000 µg nitroglycerin, 5000 U heparin, and 10 mL Rotaglide in 500 mL normal saline solution. 

Per lab protocols, any no-reflow or slow-flow was treated with intracoronary nicardipine or adenosine. Heparin was used for periprocedural anticoagulation in all patients and all were pretreated with clopidogrel per standard practice for elective coronary interventions. Since all patients were planned as RA in order to facilitate stent placement, burr sizes were chosen for plaque modification rather than to obtain an optimal angiographic result, and thus were undersized to arterial lumen diameter. 

The primary aim of this study was to demonstrate that RA is safe and feasible when used for plaque modification in order to facilitate stent deployment in patients with both severe AS and calcific CAD prior to TAVR. Safety was measured by a composite of intraprocedural hemodynamic parameters and intraprocedural/postprocedural major adverse cardiac events.

Intraprocedural hemodynamic data points. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and need for vasopressors were noted. Cardiac catheterization procedural reports (hemodynamic monitoring reports by Mac-Lab data [GE Healthcare, Inc] and nursing notes) were manually reviewed in detail by the study investigators. Any dysrhythmias were noted and all medications used during the procedure to counteract the hemodynamic events were recorded. Baseline and lowest values during the procedure for SBP, DBP, MAP, and HR were recorded.

Angiographic and clinical data points and adverse events. The study investigators reviewed the angiograms and the procedural reports to collect all study data points, including burr sizes, number of burr runs, and procedural times. Angiographic stenosis and lesion characteristics were assessed by visual estimation. Adverse events, such as coronary perforation, slow-flow or no-flow (requiring intracoronary vasodilators), and flow-limiting dissections requiring additional stent placement were recorded. Any use of temporary pacemaker (either prophylactic or urgent) or mechanical circulatory support device was recorded. All vascular complications related to access site were also recorded. Contrast nephropathy (defined as >0.5 mg/dL rise in creatinine or >25% rise in creatinine within 48 hours), death during hospitalization, and length of stay were recorded. Troponins were not routinely checked post procedure per standard practice at our institution unless clinically indicated. Myocardial infarction was defined as electrocardiographic changes consistent with myocardial infarction with or without chest pain or troponin elevation when checked for chest pain or as ordered by the treating physician.

Statistical analysis. Continuous variables are reported as means ± standard deviations and categorical variables as percentages. Comparisons of continuous variables were performed using the paired two-tailed Student’s t-test. A P-value <.05 was considered statistically significant. All analyses were performed using GraphPad Prism 5.

Results

Baseline clinical characteristics. Baseline characteristics of the 29 patients with severe AS are presented in Table 1. Subjects were elderly (mean age, 79.8 ± 8.8 years) and predominantly male (55.2%). All patients had echocardiographic evidence of severe AS (mean aortic valve gradient was 40.3 ± 9.8 mm Hg). Those with a mean gradient of <40 mm Hg had been deemed to have severe low-flow AS after further invasive testing. Mean left ventricular ejection fraction was 56.4 ± 12.9%. Echocardiographic data are presented in Table 2. All patients were on aspirin and statin. 

Angiographic characteristics and procedural data (Tables 3A and 3B). Femoral access sites and 7 Fr sheaths were utilized in all patients. Coronary artery distributions of the index lesions were as follows: left anterior descending coronary artery, 55.2%; right coronary artery, 37.9%; and left main coronary artery, 6.9%. Mean stented length was 33.9 ± 18.3 mm and 9 patients (31.0%) required overlapping stents. The mean lesion length was 32.3 ± 7.7 mm. All lesions had heavy calcification on fluoroscopy. Mean diameter stenosis was 86.3 ± 7.6%. Multivessel PCI was performed in 40% of patients in the same setting (RA in more than 1 vessel was performed in 16.7%). Mean burr size was 1.62 ± 0.19 mm and 83.3% had ≥4 burr passes. All index lesions underwent stent placement post atherectomy (mean, 1.8 stents). Mean total fluoroscopic time was 33.1 ± 17.9 min, mean contrast volume was 242 ± 104.1 mL, and mean radiation dose was 2617.50 ± 1729.07 mGy (air kerma). A prophylactic temporary pacemaker was placed in 17 patients (58.6%). 

(Tables 4A and 4B). There were significant intraprocedural drops in SBP, DBP, MAP, and HR during RA. However, they were transient and recovered spontaneously or with intravenous bolus of fluids and/or vasopressor without need for continuous infusions. None were associated with prolonged chest pain or ST changes. Two patients needed unplanned temporary pacemaker placement; pacemakers were removed at the end of the procedure. All procedures were performed under conscious sedation and no patient required intubation. No procedures were aborted. There was no coronary perforation. All patients received intracoronary vasodilators via the Rotaglide cocktail and most had liberal use of nicardipine and nitroglycerin at the start of (and in between) burr runs. Mean doses of directly administered intracoronary nicardipine and nitroglycerin were 640 ± 258.3 µg and 223 ± 130 µg, respectively. One patient had transient no-reflow (3.4%) and 2 patients (6.9%) had RA-related non-flow limiting dissections (successfully treated with additional stent placement). No patient had a groin hematoma requiring vascular surgery or blood transfusion, 1 patient (3.4%) had a pseudoaneurysm. No patient had contrast-induced nephropathy. Mean length of stay was 2.5 ± 2.4 days. There were no procedural or in-hospital strokes. No myocardial infarctions were noted. TAVR was subsequently performed in 24 patients (82.8%) as a staged procedure. 

Discussion

The main finding of this study is that coronary RA for severe calcific CAD is safe and well tolerated in elderly patients with severe AS. There is limited information on the best strategy for managing concomitant CAD in patients being considered for TAVR. There is an ever-present concern that unrevascularized CAD will result in higher complication rates during TAVR. Most TAVR studies have excluded patients with unrevascularized CAD due to this valid concern.^3,6 However, in real-life scenarios, a large percentage of patients being considered for TAVR (40%-75%) have significant CAD.^3,12-14 Thus, this is an issue of significant clinical concern. There is limited information on the safety of PCI in patients with severe AS. In one of the largest such studies, Goel et al published a report on 254 patients with severe AS undergoing PCI.¹⁵ In this single-center study, which included all patients treated over a 10-year period, the authors reported a 30-day mortality rate of 4.3%, which was no different from propensity-matched controls without AS. However, those with a higher STS score had a significantly higher mortality. The report does not mention if RA was used in any of these patients. The publication does not specify if any patients were excluded from pre-TAVR PCI due to heavy calcification. 

Severe coronary calcification is considered a high-risk feature for PCI and is associated with a lower procedural success rate and higher complication rate following PCI.^16-20 Unfortunately, the prevalence of heavily calcified lesions in elderly patients with severe AS is high.^21-23 Lesions with heavy calcification are best treated in many cases with RA, which results in a higher procedural success rate.²⁴ Recent data continue to support use of RA in calcified coronary lesions. A report from the ROTATE (Planned vs Provisional Rotational Atherectomy for Severe Calcified Coronary Lesions) multicenter registry compared outcomes in 358 patients with planned RA vs 309 patients with provisional RA.⁹ The study found that procedural time, fluoroscopy time, contrast volume, number of predilation catheters used, and in-hospital major adverse cardiac events were all significantly lower in the planned RA group.

Traditionally, interventional cardiologists have been reluctant to perform RA in severe AS patients. In a recent report, Piccoli et al described 3 cases of successful use of coronary RA after TAVR during the same procedure.²⁵ The authors report that RA was not performed before TAVR due to concern of hemodynamic compromise in severe AS patients and due to lack of any safety data. This concern for significant hemodynamic compromise is driven by the knowledge that severe AS patients have limited cardiac reserve. During RA, there is distal microembolization of atherosclerotic debris that can cause transient myocardial dysfunction/stunning (even troponin leak), and this may be poorly tolerated in elderly patients with limited cardiac reserve due to their severe AS. Furthermore, many patients also develop heart block during the procedure due to rotation-induced hemolysis releasing adenosine. This may also result in destabilization in these patients with limited cardiac reserve. Until the advent of TAVR, there was really no good indication for RA in these patients as they mostly underwent SAVR and concomitant CABG. Thus, the literature is generally silent on the safety and efficacy of RA in these patients and not much is known about the safety and hemodynamic changes during the RA procedure. 

In this study, we demonstrate that RA can be performed safely in severe AS patients and is generally well tolerated. There were no coronary perforations. Only 2 patients had significant dissections that needed an additional stent. Considering the long lesion lengths, it is evident that these were complex calcific lesions that required multiple overlapping stents. We used small-sized burrs for plaque modification for facilitating stent delivery rather than with an aim of getting a primary RA angiographic result. This was done to reduce the risk of procedural complications, and this technique of plaque modification has been demonstrated to be safe and effective in the drug-eluting stent era.⁸ We had a 100% procedural success rate, with no myocardial infarctions. Only 1 patient had slow-flow, which responded promptly to intracoronary nicardipine. We did note a transient but significant drop in SBP, DBP, MAP, and HR during RA, with 8 patients (27.6%) needing transient vasopressor support. However, there were no clinically significant events. In no cases were the RA procedures aborted or vasopressors continued post procedure. 

To our knowledge, this is the first study published in peer-reviewed literature reporting exclusively on the safety of RA in patients with severe AS and concomitant calcific CAD. Our results show that this group of elderly patients with severe AS and calcific CAD tolerated the RA procedure well, with no intraprocedural or in-hospital stroke, myocardial infarction, death, or contrast nephropathy. This study has significant clinical implications for the practicing interventional cardiologist concerned with the safety of using RA in patients with severe AS and concomitant calcific CAD. 

Study limitations. The study has the inherent limitations of a single-center, retrospective, single-arm study. However, the study population does reflect a real-life population with severe calcific AS with multiple co-morbidities. Furthermore, the sample size, while not large, does allow some degree of confidence in the safety of the RA procedure in these patients. Since we did not have any patients with severely reduced left ventricular systolic function, the safety of RA in those patients with severe AS cannot be extrapolated from this study.

Conclusion

RA is safe and well tolerated in elderly patients with severe AS and concomitant calcific CAD. There was a significant drop in SBP, DBP, MAP, and HR during RA procedure, but this was not associated with any adverse clinical events. 

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From the ¹Department of Internal Medicine, ²Division of Cardiovascular Disease, and ³Division of Cardiothoracic Surgery, University of Kansas Medical Center, Kansas City, Kansas; and the ⁴Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Tadros reports personal fees from the Medtronic Evolut R/CoreValve program and St. Jude’s consultant OCT training. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted February 19, 2017, provisional acceptance given March 13, 2017, final version accepted March 29, 2017.

Address for correspondence: Kamal Gupta, MD, Professor, Division of Cardiovascular Diseases, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160. Email: kgupta@kumc.edu