Davide Chiumello (ed.)Practical Issues Updates in Anesthesia and Intensive Care10.1007/978-3-319-18066-3_11

11. Interventional Cardiology: The Role of the Anesthesiologist

Franco Cavaliere¹

(1)

Department of Cardiovascular Science, Catholic University of the Sacred Heart, Largo Francesco Vito, 1, Rome, 00168, Italy

Franco Cavaliere

Email: f.cavaliere@rm.unicatt.it

Keywords

Mitral clipTranscatheter aortic valve implantationTAVICath labInterventional cardiology

Recent years have seen a significant increase in the activity of interventional cardiology. Primary angioplasty has become the standard of management of acute myocardial infarction, and new techniques have been developed to treat cardiac diseases as mitral regurgitation, aortic stenosis, and atrial septal defects [1].

Advances in interventional cardiology have led to an increasing involvement of the anesthesiologist. In the activity of the cardiac catheterization lab, many procedures, as mitral clip and TAVI, require general anesthesia or deep sedation. Besides, there is the evermore frequent recourse to diagnostic coronary angiography and primary angioplasty in patients with cardiogenic shock. In this case, the anesthesiologist intervenes at an early stage in assisting in the emergency room and then transporting to the cath lab. Periprocedural management includes sedation and analgesia, monitoring and pharmacological support of circulation, and the handling of respiratory failure from pulmonary edema, while the operator focuses on the procedure. In the electrophysiology lab, sedation or general anesthesia is often necessary to carry out long-lasting procedures in poorly cooperative patients. Finally, the anesthesiologist is called to handle the complications that cause circulatory or respiratory failure or require surgery.

From the point of view of the anesthesiologist, however, the cath lab is still a working environment less familiar than the operatory theater. In fact, he/she intervenes only in a limited part of the activity performed by the interventional cardiologist. Many procedures are managed directly by the cardiologist, using local anesthesia by infiltration and mild forms of sedation, in order to avoid the risk of respiratory depression. When the presence of an anesthesiologist is needed, it is still a matter of debate if he/she should preferably be a cardiac anesthesiologist. Favorable ones argue that cardiac anesthesiologists are more familiar with the techniques to be applied in case of complications, such as the use of the intra-aortic balloon pump (IABP) or ventricular assistance, and the management of sternotomy and extracorporeal circulation and are usually able to perform transesophageal echocardiography [2, 3]. In practice, however, the choice between sedation managed by a cardiologist and an anesthesiologist (cardiac or not) is strongly influenced by the availability of the latter [4].

A further aspect is the significant differences between the cath lab and the operatory theater. In some facilities, there is a hybrid operating room, designed to perform the functions of both a cath lab and an operating room, which allows to work in a comfortable environment, characterized by areas of adequate size and amenities similar to those of an operating room. More frequently, however, the activity is performed in smaller rooms, where the space available for the anesthesia machine and anesthesiological material is limited, as it is that for the surgical team and its equipment, in the event of a complication that requires surgery. The relative difficulty of movement and access to the patient during the procedures affects the preparatory phase. Quality and stability of vascular accesses, airway control, and availability of adhesive plaques for electrical defibrillation or external pacing are particularly important. Moreover, the absence of the anesthesiologist in most of the activities performed in the room can lead to a lower confidence of nurses with anesthesiological techniques and airway management. Finally, it is necessary that the anesthesiologist periodically checks the equipment functionality and the availability of drugs and materials, maintains an elevated degree of attention during procedures that see him/her involved, and puts in place all possible measures to guarantee a safety standard as high as that present in the operating theater.

11.1 Percutaneous Mitral Valve Repair (MitraClip®)

Mitral regurgitation is a relatively frequent pathology, which can cause a progressive dysfunction of the left ventricle, up to congestive heart failure. In the past, the most common etiology was acute articular rheumatism; now it is the myxomatous degeneration of the valve, which determines the prolapse. Other possible causes are ischemic dysfunction of the papillary muscles and connective tissue diseases, such as Marfan and Ehlers-Danlos syndromes. Finally, functional insufficiency may result from the increase in size of the left atrium and ventricle. The indication for surgery (plastic repair or replacement) arises in moderate-to-severe (3 +) or severe (4 +) regurgitation, when this is associated with symptoms indicative of a significant ventricle dysfunction [5].

One of the surgical techniques used in plastic repair of the valve is the “edge-to-edge” method, proposed by Alfieri et al. in 1998. It involves the central suture of the two valve leaflets with the formation of a double orifice [6]. A similar result has been obtained with a percutaneous approach by joining anterior and posterior leaflets with a clip [7], that is, a structure of chrome-cobalt, about 4 mm wide, which is placed by a specific catheter. The catheter is introduced from the femoral vein and pushed into the right atrium and then into the left atrium through transseptal access. The tip of the catheter is advanced into the ventricle until the clip is positioned so that, by closing it, it grasps the central part of the two mitral valve leaflets and approximates them. This maneuver is carried out under a fluoroscopic and echocardiographic control, with the placement of a transesophageal probe.

The effectiveness of the percutaneous placement of a mitral clip has been investigated by numerous studies. Among them, the first EVEREST study (Endovascular Valve Edge-to-Edge Repair Study), conducted on 27 patients, showed a reduction in the degree of valvular insufficiency of one or two functional classes 6 months after the procedure [8]. The second EVEREST study, carried out on 279 patients, compared the results of mitral clip positioning with surgical intervention, 1 year after the procedure [9]. The primary objective of that study was to evaluate the percentage of patients who were still alive, had not been operated or reoperated for valve replacement, and presented a degree of insufficiency lower than moderate-to-severe (3 +). The percentage was significantly higher in surgical patients (73 %) than in patients who were treated with the percutaneous approach (55 %). Even so, the former presented more complications, mainly the need for blood transfusion and for invasive mechanical ventilation lasting more than 48 h. Four years after the procedure, the primary endpoint was still reached by more patients in the surgical group (53 %) than in the mitral clip group (40 %), but the difference was not statistically significant, and mortality was similar. However, the percentage of patients undergoing cardiac surgery for the presence of residual regurgitation was significantly lower after surgery (2 % vs 20 %) [10]. Those findings support the currently accepted indications for MitraClip® procedure, i.e., the presence of severe degenerative or functional mitral insufficiency, which meets the criteria for surgical correction, but presents a surgical risk deemed unacceptable.

11.1.1 The Role of the Anesthesiologist

A mitral clip is usually positioned under general anesthesia. The main reason is that the patient has to bear the transesophageal ultrasound probe all over the procedure, a condition that is generally poorly tolerated. Supine position and the need to maintain a relative immobility accentuate this difficulty, particularly in subjects with severe cardiac dysfunction. The procedure is indeed quite long; its average duration is about 3 h, but it is very variable. The length is influenced by patient anatomy, the possible need to place a second clip, and finally the ability of the operator. In this respect, the learning curve is quick enough, and there is often a significant shortening of the average duration of the procedure with increasing experience.

Preoperative evaluation by an anesthesiologist is an important part in the initial multidisciplinary assessment of surgical risk. Once the indication to MitraClip® percutaneous mitral valve repair is put, the informed consent is gathered, and blood unit availability is obtained (in our center, two units are requested). A light premedication with benzodiazepines may facilitate patient management. The technique can be either intravenous or inhalation anesthesia. Monitoring includes two-lead ECG, invasive blood pressure, pulse oximetry, and capnometry. It is good to have one, preferably two, venous access of a good caliber; a central venous catheter is useful, while a pulmonary artery catheter is seldom necessary. After anesthesia induction, a muscle relaxant is given, and a tracheal tube is positioned to control airways. Heparin is administered at the beginning of the procedure to maintain the activated clotting time around 250 s. Most patients are awakened in the cath lab at the end of the procedure.

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