Isolated proximal left anterior descending coronary artery (LAD) stenosis not amenable to percutaneous coronary intervention (
PCI) has traditionally been treated with conventional on-/off-pump coronary artery bypass graft (CABG) by access route median sternotomy [ Figure 1a].[ 1 , ] However, in high-risk patients, extracorporeal circulation (ECC) confers the risk of inflammation, coagulopathy, and therein associated adverse effects.[ 2 3 , ] Though off-pump coronary artery bypass ( 4 OPCAB) through full sternotomy eliminates the inherent risks of ECC in susceptible high-risk patients, however, in some patients, median sternotomy needs to be avoided entirely.[ ] 5 MIDCAB comes into play as an alternative approach to both conventional CABG and OPCAB in those patients with contraindication for the median sternotomy and ECC. Figure 1:
(a)Coronary angiogram in a patient showing calcific, aneurysmatic segments of the proximal LAD (Black arrow). (b)Coronary angiogram 1-year after
MIDCAB (LIMA-LAD) in patient 1 with intact flow in LIMA-LAD, (Black arrow). (c)Aortography provided the tentative diagosis of porcelain aorta (Black arrow tips), which was confirmed by (d)computed tomography showing near circumferential severe calcification at ascending aorta (white arrow). (e)Set up for MIDCAB with specially designed access route retractor and (f)direct LIMA harvest procedure
Coronary artery disease (CAD) is estimated to coexists in 40% to 75% of patients with severe AS.[
] The optimal treatment strategy for CAD with concomitant aortic stenosis (AS) in octogenarians is highly debated in the current era of evolving percutaneous techniques for this purpose. Contrary to earlier studies that showed very high surgical risk in combined surgery for AS/CAD, more recent studies show improved early/long-term outcomes in this age bracket with even acceptable quality of life.[ 6 7–9 -] Hence, aortic valve replacement (AVR) with concomitant CABG is still recommended as the standard therapy for these patients.[ ] 10
In a recent meta-analysis, Tarus
et al.[ ] found no significant difference both in the short-term and late mortality outcomes in elderly patients with combined AS and CAD who were treated with 11 PCI/transcatheter aortic valve implantation ( TAVI) versus surgical AVR (SAVR)/CABG. However, SAVR/CABG patients had significantly longer in-hospital and intensive care unit stays, respectively; hence recovery period was prolonged. Promising results of TAVI, especially in the high-risk elderly patients, has significantly affected current guidelines. High-risk or elderly patients who have no anatomic contraindication for TAVI may be offered either SAVR or TAVI after shared decision-making about the balance between expected patient longevity and valve durability.[ ] This is owing to promising results of the various percutaneous available techniques for the treatment of valvular heart diseases. 10
hybrid principle presented here is an attempt to combine the best evidence-based interventions of both percutaneous techniques and surgical techniques to improve patient outcomes. Best evidence-based surgical intervention, especially in the elderly multimorbid, is achieved utilizing the superior patency rates–related outcome of LIMA-LAD (left internal mammary artery-left anterior descending artery) grafts over PCI in suitable patients avoiding the use of ECC through a minimally invasive access route.[ ] 12 Case 1
An 83-year-old male dialysis-dependent presented to our emergency department with worsening left thoracic pain and pressure sensation accompanied by shortness of breath. He had previously experienced repeated episodes of chest pain over a 4-week period. His past medical history was significant for congestive heart failure (New York Heart Association [NYHA] class III), chronic obstructive pulmonary disease, atrial fibrillation, and arthritis. In 2014, an infrarenal abdominal aortic aneurysm was successfully treated with endovascular stent graft implantation. Transthoracic echocardiogram (TTE) revealed severe aortic valve stenosis (mean gradient across the aortic valve 47 mm Hg, aortic valve area 0.7 cm
2), left ventricular ejection fraction (LVEF) was 60%. At the same time, pulmonary artery systolic pressure was measured at 44 mm Hg. There was mild (I°) mitral/tricuspid valve regurgitation, respectively. A coronary angiogram revealed a 25% distal Left Main (LM) stenosis, 75% proximal left anterior descending artery (LAD) stenosis, and 70% ostial circumflex ramus (RCX) stenosis, respectively. The right coronary artery was normal post previous PCI/stent-graft implantation.
The patient’s case was presented and discussed in the Multidisciplinary Heart Team (MDH). In the context of severe symptomatic AS combined with significant 3-vessel CAD in an elderly, frail, and overall comorbid patient (Euro Score II 33.8/STS score 8.4), and he was scheduled for an alternative approach, namely, staged management. Prior to initiation of the
hybrid procedure, computed tomography aortography was obtained, which revealed kinking and tortuous right iliac vessels. There was equally a tentative diagnosis of type II endoleak of the abdominal stent graft. At first, the patient was scheduled for MIDCAB on the seventh day after admission. On the scheduled day for the surgery, coronary revascularization was accomplished by sewing the left internal thoracic artery to LAD [ Figure 1e- f]. The postoperative course was uneventful and he was transferred to our cardiology unit on the fifth postoperative day for both PCI (LM/RCX PCI and drug-eluting stent-graft implantation) and TAVI. This was accomplished on the 10 th day after hospital admission. The patient was discharged home on the 20 th-day post-admission. The last follow-up at 1 year after the index procedure revealed an episode of noncardiac-related hospital admission necessitated by an episode of syncope during dialysis. On that occasion, a diagnostic catheterization ruled out any cardiac cause [ Figure 1b]. He has since then resumed his day-to-day activities. He is currently in NYHA functional Class II and TTE showed improved cardiac function. Case 2
An 85-year-old female with known AS on maximal medical therapy was admitted to our emergency department with the diagnosis of decompensated heart failure associated with non-ST-segment elevation myocardial infarction. Her past medical history was significant for hairy cell leukemia and early phase myelodysplastic syndrome, which led to pancytopenia. Initiation of rituximab-mono chemotherapy was scheduled for the period after treatment of her cardiovascular disease. Her past medical history was significant for atrial fibrillation, hypertension, chronic bronchitis, and chronic renal failure II. Emergency catheterization revealed a 2-vessel disease with severe LAD and RCX stenosis. The patient underwent primary
PCI with the successful deployment of drug-eluting stents in the RCX. PCI to the LAD was attempted but failed due to a combination of vessel tortuosity, severe calcification, and failure to sufficiently expand the lesion. She was admitted, thereafter to our cardiac care unit for further treatment and recompensation awaiting scheduling of MIDCAB prior to TAVI. Ten hours postintervention, the patient’s systolic blood pressure gradually decreased despite the combined use of dobutamine and noradrenaline. There was ST depression over the anterior lead. The diagnosis of hemorrhagic/cardiogenic shock was established, with an increased arterial lactate level. Urgent repeat PCI revealed unaltered thrombolysis in myocardial infarction 3 flows over LAD and RCX. Further inspection of the groins revealed active bleeding from her groin access route, which was treated successfully percutaneously. Repeat TTE revealed that peak aortic jet velocity was 4.2 m/s, aortic valve area was 0.6 cm 2, and the LVEF was 30%. We decided that intervention was necessary to improve the patient’s hemodynamic state. First, balloon aortic valvuloplasty was performed to later facilitate the insertion and deployment of the aortic valve prosthesis, with a 20-mm Osypka balloon®, Rheinfelden, Germany. The patient was transferred to the intensive care unit in a significantly improved state pending preparation for MIDCAB/ TAVI, which were performed successfully 2 and 5 weeks later, respectively. The patient was discharged home 5 days after transcatheter aortic valve replacement (TAVR) in a markedly improved cardiopulmonary state. At a 3-month follow-up, apart from regular clinic admissions due to her leukemia, she has been in a much improved and stable cardiopulmonary state with currently NYHA class II. Transthoracic echocardiography showed improved cardiac function. Unfortunately, the patient died 6 months after the index procedure due to severe pneumonia, which led to multiorgan failure. Case 3
An 84-year-old male patient presents with worsening shortness of breath accompanied by a burning and squeezing sensation of the chest region. He was recently diagnosed with AS and had been scheduled for diagnostic and clinical evaluation prior to
TAVI. Significant in his past medical history included bradycardia and atrial fibrillation, which necessitated implantation of VVI-Pacemaker 2 months prior to his current hospital admission. Further history revealed hypertension, hyperthyroidism, and benign prostate hyperplasia. A coronary angiogram revealed a 2-vessel CAD with chronic total occlusion of LAD and localized RCX dissection. PCI was complicated by heavy calcification of the proximal LAD, which proved balloon uncrossable, and placement of the balloon was extremely difficult. After multiple unsuccessful attempts with manipulation to position a balloon, the procedure was terminated to be discussed in our MDH. He was later referred to our cardiac surgery unit for MIDCAB prior to TAVI. After left anterolateral sternotomy, adhesions made further access cumbersome and therefore converted to OPCAB with median sternotomy. The left internal thoracic artery was thereafter successfully sewn to LAD. After an uncomplicated postsurgery episode, he was transferred to the cardiology unit on the 10 th day postsurgery. TAVI was then successfully performed 2 days later.
The patient recovered well during the postoperative period and was discharged home 10 days after the procedures. At the latest follow-up, 1 year postsurgery, he has since then resumed his day-to-day activities. He is currently in NYHA Class II and TTE showed improved cardiac function.
An 84-year-old man with 2-month escalating exertional chest pain that abates with 10 minutes of rest presented to our out-patient clinic for further evaluation. His CAD risk factors as revealed by his medical history included hypertension, dyslipidemia, and diabetes mellitus. He was recently diagnosed with atrial fibrillation and has since then been maintained on warfarin. Ambulatory TTE revealed grade III AS with a mean gradient 47 mm Hg, arotic valve area 0.7 cm
2, and LVEF 52%. He was, thereafter, scheduled for coronary angiography, which revealed a 3-vessel CAD with significant lesions of LAD, RD, and RCX with no significant right coronary artery lesion. There was extensive calcification on the wall of the aorta as well as the course of the vessels [ Figure 1c- d]. A percutaneous coronary intervention of the LAD/RD was tried, however, though RD was crossable peripheral LAD proved uncrossable and the intervention was terminated. Due to his frailty accompanied by recently diagnosed Parkinsons’s disease, he was scheduled for MIDCAB, which was successfully carried out 10 days after admission. Three days after the MIDCAB procedure, LM/RD and RCX PCI and stent-graft implantation were performed, followed by transfemoral TAVI in the hybrid suite simultaneously. The patient was discharged home 3 weeks after initial hospital admission. One year ambulatory follow-up revealed a symptom-free patient and NYHA Class II under the care of his general practitioner. (Date and number of IRB approval: 23/03/2021, Institutional Review Board approval number A2021-0078). HOW WE PERFORM THE
MIDCAB-PROCEDURE AND DEVICES
Extensive description of technical aspects of the
MIDCAB procedure has been previously described.[ ] 13 DISCUSSION
MIDCAB technique is indicated for isolated complex proximal LAD stenosis when PCI is not successful. For this purpose, strict specific contraindications need to be observed for a successful patient selection and good outcomes. These contraindications include occluded coronary vessels, emergency CABG, unfavorable chest anatomy, adhesions, and finally intramyocardial or severely calcific lesions. Herewith, we have demonstrated the feasibility, efficacy, and safety of TAVI after MIDCAB through left-anterolateral access and PCI/stent-graft implantation in a very small number of patients. This approach can be applied simultaneously or in a staged fashion to treat complex multifaceted CAD and AS in multimorbid octogenarians depending on team preference or available logistics. All patients received PCI/stent-graft implantation prior to or after surgery as the case may be [ Table 1]. In the presented cases, a dedicated hybrid approach completely eliminated aortic cross-clamping and thereby involved ischemic time; hence global myocardial ischemia could be avoided. Avoidance of ECC time equally prevented inherent inflammatory response, coagulopathy, and possibly kidney injury that may be associated with ECC.[ 3 , ] The 4 hybrid approach also reduces the mortality and morbidity encountered in combination surgery for aortic valve stenosis and CAD, especially in frail severely sick octogenarians, which may be as high as 8%.[ ] Our patients 3 and 4 though had Euro Score (7.7 and 7.6) and STS values (4.7 and 2.5), but these scores do not incorporate frailty. The prognostic value of frailty in patients referred for cardiac surgery has not been sufficiently explored. There are indications that in fact frailty in patients scheduled for cardiac surgery confers an increased risk of postoperative complications including up to 5-fold increased risk of nonhome discharge and 4-fold increased 30-day mortality. Our patients 3 and 4 had comparatively lower Euro Score II and STS values, but were extremely frail and therefore categorized as high risk.[ 8 14 , ] 15 Table 1:
Characteristics of patients who underwent
hybrid management of CAD and AVS
Another critical aspect worth discussing in our patient cohort is the existence of atrial fibrillation, which was not attended to during
MIDCAB surgery. These patients were subsequently evaluated for catheter-based atrial fibrillation ablation/left atrial appendage occluder implantation. Since, the patients had been stable under adequate frequency control and anticoagulation, their general practitioners have been hesitant in terms of reference for further interventions.
The proportion of patients hospitalized for AS increased in recent years in conjunction with the higher life expectancy and introduction of the
TAVI.[ ] Advanced age being a predisposing factor for CAD, it will be expected that increasingly elderly, high prohibitive risk patients with AS, and concomitant CAD will be admitted for surgical/percutaneous treatment.[ 9 ] The 10 hybrid approach, which combines surgical best practice as can be appreciated with LIMA, and its superior long-term patency and interventional cardiologists experience with PCI/ TAVI herald a new dawn for high-risk surgical elderly patients with complex, multilayered cardiac pathologies. In our opinion, MDH consultation with each patient is a key to optimal patient selection and subsequent implementation of the hybrid approach.
Another key aspect worthy of future exploration is the decision for appropriate patient-tailored modality of
TAVI. In this context, Mayr et al. recently presented 12 patients treated successfully by means of hybrid OPCAB/ MIDCAB with different modalities of TAVR routes, namely, transaortic, transfemoral, trans-subclavian, and transapical. Transapical TAVR using the same access route left anterolateral thoracotomy is an attractive option in patients treated by means of MIDCAB.[ ] 16
The clinical impact of the presence of significant CAD at the time of
TAVI remains controversial.[ 11 , ] In patients with CAD scheduled for 17 TAVI, the decision to revascularize, which lesions to revascularize and the optimal timing for revascularization remains a highly debated topic. However, revascularization prior to TAVI of proximal, amenable lesions remains a commonly accepted practice globally. Further developments will be induced by adequately powered future randomized, controlled trials. Coronary artery reaccess, though possible in most cases after TAVI, may be extremely challenging in some cases. In those patients who for various reasons received TAVI prior to coronary intervention or in those with the progression of CAD years after TAVI in need of coronary intervention, it poses a challenging experience, especially in long self-expanding valves.[ ] We advocate prior complete revascularization, prior to 18 TAVI especially since surgery is also well equipped with a low-risk, safe, and feasible armamentarium as has been demonstrated with the MIDCAB/ OPCAB technique. The preferred sequence whether MIDCAB/ OPCAB followed by PCI or vice versa should be evaluated in a Heart-Team, especially in nonemergency cases. A patient-tailored, Heart-Team–led approach is a key to the successful implementation of the hybrid procedure and decision should be made taking center experience and volume into consideration as centers with extensive experience also produce best results.
The multidisciplinary decision making (Heart-team) team at our center comprises primarily of clinical cardiologists, interventional cardiologists, cardiac surgeons, and cardiac anesthesists. This team meets once every week to discuss cases at hand, but can also be consulted for unplanned cases in need of multidisciplinary attention. Decisions made in the heart team are meticulously documented in our standardized heart team protocol signed by all participating specialities and filed in the patient chart. Other specialities like imaging specialists can be involved in certain circumstances as the case may be. Further details on the MDH team approach including recommendations for requirements of a heart valve center are detailed in the ESC/EACTS (European Society of Cardiology/European Association for Cardio-Thoracic Surgery) guidelines for the management of valvular heart diseases as well as guidelines on myocardial revascularization.[
19 , ] 20 CONCLUSION
In a select group of elderly, frail, and high prohibitive risk patients with CAD and severe symptomatic AS, a staged approach with
MIDCAB/ OPCAB and PCI followed by TAVI can be safely performed with excellent outcomes. A staged approach in this patient cohort allows for optimal recovery after each intervention and should be individually tailored based on a Heart Team decision. Larger prospective randomized studies are required to confirm the feasibility of this treatment strategy. Financial support and sponsorship
Conflict of interest
A. Öner received honoraria of Medtronic. All other authors have no conflict of interest to declare.
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