Percutaneous Aortic Valve Implantation in Patients with Coronary Artery Disease: Review of Therapeutic Strategies
From the †Department of Cardiology, Rabin Medical Center, Petach Tikva, and the 'Sackler' Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel, ‡Onassis Cardiac Surgery Centre, 1st Cardiology Department, Athens, Greece.
The authors report no conflicts of interest regarding the content herein.
Manuscript submitted July 6, 2009, provisional acceptance given July 20. 2009, and final version accepted July 27, 2009.
ABSTRACT: The optimal treatment for coronary artery disease in patients who are candidates for percutaneous aortic valve implantation (PAVI) remains unclear. The operating team should take into consideration that the symptoms of ischemic heart disease could be identical to those of severe aortic stenosis and that performing percutaneous coronary intervention (PCI) in these frail patients prior to, or following PAVI, is not trivial. We describe a patient with severe aortic stenosis and significant coronary artery disease who was treated during the same interventional session: PCI that was followed immediately by PAVI. We review the different treatment strategies for patients who are candidates for PAVI and have coronary artery disease, discuss the relative advantages of each approach, and propose an algorithm for their treatment.
J INVASIVE CARDIOL 2009;21:E237–E241
Key words: PaceC elevation
Calcific aortic stenosis is associated with atherosclerosis risk factors1–3 and is common among patients with coronary artery disease (CAD).4 The treatment of choice for patients with severe aortic stenosis and CAD is cardiac surgery that includes aortic valve replacement and implantation of coronary artery bypass grafts. However, many patients are at high risk of mortality and morbidity and are not referred for surgery.5,6 In 2002, the first-in-man use of percutaneous aortic-valve implantation (PAVI) was described, opening a new era of aortic stenosis management.
Currently, the best treatment for CAD in patients who are candidates for PAVI remains unclear. Since PAVI alone often provides patients with adequate angina relief, physicians may be inclined to treat the coronary disease conservatively. However, many centers favor a staged approach in which a lower-risk procedure, usually percutaneous coronary intervention (PCI), is followed by PAVI several weeks later. Experience with single-stage procedures in which the patient is treated with PCI followed immediately by PAVI is still limited.
Case Description. An 87-year-old female was examined in our department for deteriorating functional capacity (NYHA Class IV). Her medical history revealed an episode of acute coronary syndrome 1 year previously. Coronary angiography at that time revealed significant coronary stenosis only in the proximal right coronary artery (RCA). Treatment consisted of PCI with deployment of a bare-metal stent. The patient had many comorbidities such as chronic renal failure and chronic anemia, and was status post hemorrhagic stroke several years before.
On physical examination at admission, a 3/6 systolic murmur was heard at the base of the heart. Echocardiography revealed good systolic left ventricular function with an ejection fraction of 60%. Significantly high gradients were noted over the aortic valve (99/59 mmHg), and the calculated valve area was 0.8 cm2. The diagnosis was severe aortic stenosis. There was mild aortic valve regurgitation and the ascending aorta was not dilated.
The patient was considered a very poor candidate for conventional aortic valve replacement surgery owing to her relatively advanced age, significant frailty, and reduced rehabilitation capacity secondary to the previous stroke. The logistic EuroSCORE predicted a 31% risk of mortality; the Logistic Parsonnet score was 35%. The patient was referred to our PAVI screening program and was found to be eligible for the procedure.
The patient underwent PAVI in March 2009. The procedure was performed under general anesthesia and continuous transesophageal echocardiography (TEE) monitoring. Coronary angiography, performed before the aortic valve was crossed with the guidewire, demonstrated no significant obstruction in the left coronary system (Figure 1A) and near-total occlusion of the proximal RCA stent (Figure 1B). After discussing the clinical situation, we opted for a single-stage procedure wherein we would perform PCI to the RCA and soon thereafter continue with PAVI as planned. The PCI was performed with a 15 x 3.5 mm scoring balloon at 12 atm inflation pressure (Figure 1C), with excellent angiographic results (Figure 1D). A stent was not deployed. Once good flow in the RCA was confirmed and the patient was hemodynamically stable, we completed the PAVI process. A temporary pacemaker was inserted to allow for rapid pacing and for potential heart block. Following mini-surgical cutdown in the groin, several balloon inflations were performed in the aortic valve. A 26 mm Edwards-Sapien balloon-expandable aortic valve (Edwards Lifesciences, Inc., Irvine, California) was then delivered through a 24 Fr introducer sheath (Figure 2A), and the balloon-valve complex was inflated under rapid ventricular pacing (220 Hz) (Figure 2B). Fluoroscopy and aortography revealed that the valve was in the exact position, with no paravalvular leakage, and that the coronary ostia were open (Figures 2C and 2D). On echocardiography, there was a decrease in the aortic valve gradients (from 102/72 to 11/6 mmHg) and an increase in the valve area (from 0.8 to 1.6 cm2). The vascular access was closed surgically.
The patient was transferred to the intensive care unit, and extubation was performed 2 hours later. One day after the procedure, the patient commenced ambulation. There was no evidence of significant vascular or hemorrhagic complications, arrhythmias, or conduction disturbances. The patient was discharged from the hospital 4 days after the procedure in excellent condition, with early evidence of significant clinical improvement. The improvement was sustained on clinical and echocardiographic follow up 2 months later.
Discussion. We report herein on a patient whose PCI was followed immediately by PAVI during the same interventional session. We need first to clarify several points in order to analyze the different possible strategies for the treatment of combined CAD and severe aortic stenosis in candidates for PAVI:
1) The symptoms of ischemic heart disease could be identical to those of severe aortic stenosis. In many clinical scenarios, it is impossible to be entirely confident that the symptoms, such as exertional angina and dyspnea, are secondary to valvular disease only and are not related to coronary disease. Therefore, we suggest that PCI be performed in candidates for PAVI who have significant stenosis in a major coronary segment. Nevertheless, it is possible that PAVI alone will improve the flow in the coronary arteries. A recent study of PAVI-associated changes in coronary flow showed that after valve implantation, there is usually an increase in flow in the proximal coronary arteries, probably reflecting an improvement in the cardiac output or a decrease in the left ventricular end-diastolic pressures.7
2) PAVI is a high-risk procedure when performed in patients with significant coronary artery stenosis. During aortic valve balloon inflations, the operator performs rapid ventricular pacing (200–220 Hz) for several seconds in order to decrease the contractility and flow through the aortic valve and thereby lower the risk of valve migration during implantation. During that time, the systemic blood pressure drops sharply, which places patients with significant CAD in danger. Therefore, we suggest that it is better to perform the lower-risk procedure (i.e., PCI) before the higher-risk one (i.e., PAVI). However, it should be noted that when performing PCI first for ostial left main or ostial RCA stenosis, the coronary stent might be localized proximally inside the aorta, and when PAVI will be performed next, the valve stent might press on the coronary stent and coronary flow could be jeopardized.
3) Performing PCI after PAVI is not trivial. There are many different systems available for PAVI. All the valve stents must assure normal blood flow through the coronary ostia and permit, to the extent possible, free access to the coronary arteries. Some prostheses are designed to be positioned below the coronary ostia, and others to extend above the coronary ostia. With either type, the struts may overlie the ostia. The relatively open-cell configuration of the prostheses does not guarantee that the struts will not interfere with catheter intubation of the coronary ostia or that aggressive manipulation will not dislodge a tenuously seated valve or its tissue overgrowth. Translocation of calcified valvular tissue with blockage of a coronary ostium only rarely complicates PAVI, but it is highly dangerous.8 Few data are available on the outcome of PCI performed after PAVI. Zajarias et al9 described an 85-year-old patient who underwent PCI with a stent 15 months after PAVI with an Edwards system. More recently, Geist et al10 described a 79-year-old patient who had an acute myocardial infarction 3 months after undergoing PAVI with the CoreValve system. Because the CoreValve system is relatively long, the only way to perform a subsequent PCI is to cross the valve-stent struts. Although both these procedures ended successfully without complications, performing PCI after PAVI requires a high level of expertise and probably “some luck” as well. Therefore, whenever possible, the operator should treat the coronary artery stenosis before the aortic stenosis.
4) PCI is a high-risk procedure when performed in patients with severe aortic stenosis. Evidence suggests that PCI is associated with a poor outcome in patients with severe aortic stenosis,11 although, theoretically, performing PCI after PAVI might decrease the valve gradients and lower the risk of coronary intervention. Nonetheless, we do not recommend it because of the danger of engaging the coronary ostia after the valve intervention, as described above, and the risk associated with a transient low perfusion state during the course of rapid pacing in patients with obstructive coronary disease.
Some operators who perform PCI in candidates for PAVI wait for a period of days to weeks before performing the PAVI (staged procedure). This method might be advantageous because by performing the lower-risk procedure first (PCI), the physician can evaluate the patient’s symptoms and the need for the higher-risk procedure (PAVI). In addition, allowing for stent endothelialization conceivably decreases the risk of stent thrombosis during the intervals of little coronary flow that are an integral part of the PAVI procedure. Others may elect to perform the complex PCI when the patient is already anesthetized in preparation for PAVI. This way, the operator may better handle the risk of periprocedural heart failure, which may occur during or following PCI in patients afflicted by severe aortic stenosis.
In this report, we described a single-stage procedure wherein PCI was immediately followed by PAVI. This method is advantageous in that it may considerably decrease the total hospitalization time, a major source of morbidity in elderly patients. Decreasing the hospital stay will probably decrease the total cost of the procedure and reimbursement, which is appealing for the medical providers. Moreover, since PCI is often a high-risk procedure in patients with aortic stenosis, by lowering the gradients along the aortic valve soon after performing PCI, one can hypothesize that the long-term outcome of the PCI might be improved. However, there are not enough data on the safety of performing the single-stage procedure. One of the disadvantages is the risk of coronary stent thrombosis during the intervals of reduced coronary flow while performing rapid ventricular pacing, or the risk of performing urgent cardiopulmonary bypass due to complication in these high-risk patients. On the basis of these findings, we have developed an algorithm for the treatment of CAD in a PAVI candidate (using either a transfemoral or transapical approach) (Figure 3). First the physician should assess the coronary arteries and/or bypass vessels. If there is no significant obstruction in a major coronary segment, PAVI should be performed without delay.
In a case where there is a significant obstruction in a major coronary segment, the team should evaluate the complexity of performing complete revascularization by PCI. In a case where the patient has significant coronary disease, but the disease is not anticipated to be unduly complex for revascularization using PCI, the team needs to decide when to perform the PAVI procedure: immediately after the PCI (single-stage procedure) or several days or even weeks apart (multistage procedure), taking the relative advantages of each as well as the patient’s wellbeing into account.
When the PCI seems high-risk and/or complex, the team should reassess the patient’s surgical risk. If that risk is not extremely high, the decision should be to pursue bypass and aortic-valve replacement surgery. “Off-pump” bypass surgery, combined with PAVI or other hybrid procedures, should be considered depending on the technical feasibility and/or medical center’s expertise.12 If the surgical risk seems very high, then PCI followed by PAVI (staged or during a single session) should be considered. Alternatively, in this high-risk setting, the team should consider performing only partial coronary revascularization and/or aortic-valve balloon valvuloplasty possibly as a temporary or bridge treatment before PAVI.
An operator performing PCI in a candidate for PAVI also needs to decide whether to implant a stent and what type of stent should be used. Bare-metal stents significantly increase the need for repeat intervention at the stent site which, in some cases, means crossing the valve stent struts during PAVI. However, drug-eluting stents are limited by the need for long-term dual antiplatelet therapy with a somewhat augmented risk of bleeding — an especially important consideration in current PAVI candidates who are usually frail patients with many co-morbidities. No matter which coronary stent is chosen, every effort should be taken to ensure that the implanted valve will allow future engagement of the coronary arteries.
Conclusion. In summary, there are many different treatment options for combined CAD and severe aortic stenosis in candidates for PAVI. We have developed an algorithm that may help decision-making while approaching this common clinical scenario.
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