Michael Andritsos

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2009

The hybrid operating room is the venue for transcatheter therapy with the convergence of 3 specialties: cardiac surgery, cardiovascular anesthesiology, and interventional cardiology. Transcatheter aortic valve replacement is proof that cardiac specialists have embraced the endovascular revolution. Because pharmacologic conditioning and ischemic myocardial conditioning are safe and effective, they are currently the focus of multiple trials. Angiotensin blockade, anemia, and endoscopic saphenous vein harvesting worsen outcome after coronary artery bypass graft (CABG) surgery. Although off-pump CABG surgery is equivalent to on-pump CABG surgery, it may improve outcomes in high-risk groups. Although percutaneous coronary intervention (PCI) significantly decreases mortality after myocardial infarction, the evidence is less convincing for intra-aortic balloon counterpulsation. Even though prasugrel recently was approved for platelet blockade in PCI, it may be superseded by ticagrelor. Although PCI and CABG surgery appear equivalent for multivessel coronary disease, CABG surgery lowers revascularization rates and also has superior outcomes in diabetics and the elderly. Hetastarch and N-acetylcysteine both increase bleeding and transfusion in cardiac surgery. Factor VII can treat life-threatening bleeding, but its safety requires further evaluation. Because eltrombopag and romiplostim stimulate platelet production, they may have a future role in hemostasis after cardiac surgery. Even though fenoldopam, atrial natriuretic peptide, and sodium bicarbonate are nephroprotective, further trials must confirm these findings. Intensive insulin therapy offers no further outcome advantage and significantly increases hypoglycemic risk. The past year has witnessed the advent of a new clinical venue, new devices, and new drugs. The coming year will most likely advance these achievements.

Innovations in Aortic Disease: The Ascending Aorta and Aortic Arch

Significant innovations have defined the approach to the proximal thoracic aorta. Aortic proteolysis predisposes to dissection and aneurysm. Losartan may prevent aortic root dilation in Marfan syndrome. The Loeys-Dietz syndrome mandates early aortic intervention. Because genetic aortopathies have a multicenter registry, further aortic molecular advances are likely. Acute intramural hematoma (IMH) may be due to aortic dissection with unrecognized microintimal tears. Type-A IMH is often a surgical emergency, whereas type-B IMH often requires medical management. Because preoperative ischemia predicts mortality in type-A dissection, it is logical to classify this disease by ischemic presentation. Because advanced age worsens the outcome in type-A dissection, transcatheter interventions should be urgently developed for this high-risk subgroup. Aortic arch repairs shorter than 45 minutes in duration are safely performed under deep hypothermic circulatory arrest with/without perfusion adjuncts. Bilateral antegrade cerebral perfusion (ACP) offers the best neuroprotection for complex repairs longer than 45 minutes. Axillary artery cannulation improves outcomes in proximal thoracic aortic procedures. Contralateral hemispheric ischemia is possible with unilateral ACP because cross-cerebral perfusion may be inadequate. Arch repair with ACP and moderate HCA is safe and effective and represents a research opportunity for pharmacologic ischemic preconditioning. Antegrade thoracic aortic stenting for DeBakey 1 dissection thromboses the distal false lumen to improve long-term aortic outcomes. Endovascular arch repair is feasible and may soon be done off-pump. These described innovations have collectively ushered in a paradigm shift in diseases affecting the ascending aorta and aortic arch.

The Complications of Uncomplicated Acute Type-B Dissection: The Introduction of the Penn Classification

Uncomplicated acute type-B aortic dissection (ATBAD) is a misnomer because it has subgroups with excessive mortality risk. The Penn classification has designated these ATBAD presentations as class-A because they initially are characterized by the absence of malperfusion and/or aortic rupture. The Penn classification also has designated class-A high-risk subgroups as type I and low-risk subgroups as type II. The risk factors for Penn class-A type-I presentations relate to medical therapy; aortic anatomy, and dissection extent as outlined by the DeBakey classification. Tight medical therapy significantly protects against aortic complications. Beta-blockade, angiotensin inhibition, and calcium channel antagonists may reduce mortality. The details of optimal medical therapy require further research. The aortic risk factors for type-I presentations include false lumen size and patency, ulcer-like projections, aortic diameter >40 mm, and intimal tear characteristics such as size and proximal location. The prognostic role of dissection extent in ATBAD remains unclear, requiring further investigation to determine its effect on natural history. Future trials in Penn class-A ATBAD should focus on type-I presentations. The Penn classification can serve as a clinical framework for trial design, laying the groundwork for future management advances. It also may provide a common language to facilitate standardized definitions, trial design, and management approaches for this high-risk patient cohort.

The year in cardiothoracic and vascular anesthesia: selected highlights from 2012.

Cardiothoracic and vascular critical care has emerged as a subspecialty due to procedural breakthroughs, an aging population, and a multidisciplinary collaboration. This subspecialty now has a dedicated professional society, recently published guidelines, and plans for standardized certification. This paradigm shift represents a major collaboration opportunity for our specialty. The rise of evidence-based perioperative practice has produced a culture of large trials in our specialty to search for solutions to the challenging outcome questions. Besides the growth in the development of evidence, the consensus conference format and postpublication peer review have both emerged as effective processes for identifying the most relevant high-quality evidence. The quest for best perioperative practice has highlighted the importance of teamwork at all phases of care with respect to transitions in care, blood component transfusion, and research misconduct. The emergence of ultrasound as a standard for central vascular access also has been emphasized in recent multisociety guidelines. There also has been a paradigm shift in the management of patients with coronary artery disease. Recent guidelines have emphasized the roles of the cardiac anesthesiologist and the interventional cardiologist as part of the heart team approach. Major recent trials in comparative effectiveness have challenged the advantages of percutaneous coronary intervention, off-pump coronary artery bypass surgery, and intra-aortic balloon counterpulsation. The year 2012 has witnessed the emergence of new paradigms of care in our specialty with the emphasis on teamwork, safety, and quality. These processes will further improve perioperative outcome.

The year in cardiothoracic and vascular anesthesia: Selected highlights from 2011

There have been rapid advances in oral anticoagulation. The oral factor Xa inhibitors rivaroxaban and apixaban and the oral direct thrombin inhibitor dabigatran recently have been rigorously evaluated. These novel anticoagulants will usher in a new paradigm for perioperative anticoagulation. Perioperative blood conservation in cardiac surgery recently has been highlighted in the updated guidelines by the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons. These recommendations reflect a comprehensive evaluation of the recent evidence to optimize transfusion practice. Transcatheter mitral valve repair continues to mature. Transcatheter aortic valve implantation for aortic stenosis has entered the clinical mainstream, with randomized trials showing its superiority over medical management and its equivalency to surgical valve replacement in high-risk patients. This transformational technology represents a major leadership opportunity for the cardiac anesthesiologist. Minimally invasive valve surgery has shown effectiveness in high-risk patients. Radial access is equivalent to femoral access for percutaneous coronary intervention in acute coronary syndromes but significantly reduces the risk of local vascular complications. Recent trials have further clarified the roles of medical therapy, percutaneous coronary intervention, and coronary artery bypass surgery in patients with significant coronary artery disease and left ventricular dysfunction. The past year has witnessed major advances in cardiovascular practice with new drugs, new devices, and new guidelines. The coming year most likely will advance these achievements to enhance the care of patients.

Con: Methylene Blue Should Not Be Used Routinely for Vasoplegia Perioperatively

h t VASOPLEGIA OR VASOPLEGIC SYNDROME (VS) is an ill-defined clinical state often characterized by low ystemic blood pressure, low systemic vascular resistance, high r normal cardiac output, and increased requirement for intraenous fluid and vasopressor administration.1,2 It is a form of asodilatory shock in which a lack of vascular tone leads to the nability to achieve an adequate perfusion pressure.3,4 This clinical scenario is often witnessed in cardiac surgery as a consequence of cardiopulmonary bypass (CPB) triggering a systemic inflammatory response. The incidence of VS after cardiac surgery is quite variable, ranging from 5% to 25%5-8 to as high as 42% in patients undergoing insertion of a left ventricular assist device for end-stage heart failure.9 VS has also been described in some patients with septic shock10-12 and in patients receiving protamine for reversal of heparin after CPB.13-16 Methylene blue (MB) is reported to have a therapeutic benefit during VS, inhibiting the vasodilatory effects of nitric oxide (NO) and other nitrovasodilators on the endothelium and vascular smooth muscle.17 Although MB has been used in the etting of VS during cardiac surgery, sepsis, and anaphylaxis, uestions remain about its indications because of the variability n defining VS. Additionally, exact dosing and routes of adinistration, timing of administration (early v “rescue therapy”), contraindications, and drug interactions of MB need further clarification. This viewpoint reviews the contradictions to the routine use of MB for perioperative vasoplegia, and why it should be used with extreme caution with proper knowledge of the clinical scenario of VS, its side effects and drug interactions, and dosing scheme. Risk factors for VS in cardiac surgery include preoperative intravenous heparin, angiotensin-converting enzyme inhibitors, -blockers, and calcium channel blockers.6,7,18,19 It has been shown that angiotensin-converting enzyme inhibitors and -blockers increase the relative risk for vasoplegia by 1.31 and .37, respectively.4,6 Additionally, the depletion of catecholamine levels during conditions of marked stress response such as myocardial infarction and angina leads to decreased vascular tone and reactivity.19 Other risk factors for VS include low left ventricular ejection fraction (ejection fraction 0.35) and preoperative heart failure although VS can occur with a normal ejection fraction.2,9 Protamine use also has been identified as a possible risk factor for vasoplegia.20 Surgery-related risk facors for VS include a higher additive EuroSCORE (odds atio 1.15 per 1-point increase) and duration of CPB (38% ncreased risk per every additional 30-minute interval [odds atio 1.38]).4,6 Vasoplegic syndrome has a poor prognosis. orepinephrine refractory vasoplegia has been associated with igher morbidity and mortality and has been reported to have a ortality rate of up to 25% when lasting longer than 36 to 48 ours.5,19,21 Vasoplegia appears to result from the dysregulation of NO synthesis and release and vascular smooth muscle cell guanylate cyclase (GC) activation.2,17 NO is produced from inducible nitric oxide synthase (iNOS) and from constitutive endothelial

Delayed Malignant Hyperthermia After Routine Coronary Artery Bypass

Malignant hyperthermia is a rare but well-described hypermetabolic disorder of skeletal muscle that can be potentially fatal if untreated. In our patient, malignant hyperthermia developed several minutes after discontinuation of the known triggering agent after an uncomplicated coronary revascularization. This case illustrates the dramatic presentation and successful management of a rare disease with a rare onset.

Innovations in Aortic Disease Management: The Descending Aorta

HERE HAVE BEEN major innovations in the clinical management for pathologies of the descending thoracic aorta. The beginning of this revolution began with the gradual introduction of endovascular interventions in the past decade. This section introduces the more recent advances that are reviewed in this article. Although serum markers such as matrix metalloproteinases and D-dimer have diagnostic utility in acute aortic dissection, C-reactive protein recently has emerged as an independent indicator of prognosis in acute type-B aortic dis- section. Although thoracic endovascular aortic repair (TEVAR) has an emerging role in complicated type-B dissection, its role in acute uncomplicated type-B dissection is yet to be deter- mined. Although underpowered, a recent landmark randomized trial showed that TEVAR is equivalent to the best medical therapy in the short term for this acute type-B subtype. Further prospective evaluation of TEVAR is required to establish con- clusively whether it should replace the best medical therapy as the treatment of choice for acute uncomplicated type-B dissec- tion. Because malperfusion in acute type-B dissection confers a significant risk for an adverse outcome, urgent intervention with open or endovascular reconstruction typically is indicated. A recent study has provided long-term acceptable data in this type-B subtype after percutaneous revascularization with inti- mal fenestration and/or aortic branch-vessel stenting. This man- agement strategy deserves further attention as the optimal man- agement of malperfusion in type-B dissection is investigated in future trials. The repair of a thoracoabdominal aortic aneurysm (TAAA) is associated with a significant risk of renal dysfunc- tion caused, in part, by ischemia and also a myoglobin release from perioperative rhabdomyolysis. Recent studies have sug- gested at least 2 nephroprotective strategies. The first strategy entails intraoperative intermittent cold crystalloid renal perfu- sion during TAAA repair to decrease renal oxygen demand; the addition of cold blood in this strategy did not enhance nephro- protection. The second strategy is to ensure lower-extremity perfusion during TAAA repair; this is associated with less myoglobin release most likely caused by reduced rhabdomy- olysis. Like the kidney, the spinal cord is significantly at risk during TAAA repair. Spinal cord ischemia (SCI) remains an indepen- dent predictor of mortality and morbidity. Although somato- sensory-evoked potentials (SSEPs) have shown diagnostic and prognostic perioperative utility, the question remains whether motor-evoked potentials (MEPs) further enhance the detection of SCI associated with TAAA repair. A recent comparison between these 2 types of spinal cord monitoring has shown that motor-evoked potentials do not add significantly to the clinical management of SCI achieved by somatosensory-evoked poten- tials alone. Although the role of perioperative drainage of cerebrospinal fluid (CSF) has gained clinical acceptance for the management of SCI in TAAA repair, its safety recently has been scrutinized in 2 large series. These recent studies show that this technique is very safe and has a low incidence of neurologic complications, which have a high mortality. Both studies emphasize the importance of limited CSF drainage to minimize the risk of intracranial hemorrhage. The endovascular repair of TAAA has triggered a renewed interest in the natural history and management of patients considered too high risk for surgical repair with left-heart bypass. A recent observational series confirmed the very poor prognosis of medically managed advanced TAAA, thus under- lining the clinical necessity for an endovascular option in this high-risk subset. The first TEVAR option in TAAA repair is for a total endovascular repair with fenestrated or branched endo- vascular stent components to not only exclude the aneurysm but also to preserve aortic branch perfusion. The second TEVAR option in TAAA repair is the hybrid approach, which uses nonfenestrated endovascular stent components for aneu- rysm exclusion and surgical transposition of aortic branches to preserve their perfusion by relocating their origin away from the extent of the nonfenestrated stent (debranching procedures). Multiple recent clinical series confirm that both TEVAR op- tions are reasonable in select high-risk patients although these techniques are still in early clinical development.

The year in cardiothoracic and vascular anesthesia: selected highlights from 2013.

This article reviewed selected research highlights of 2013 that pertain to the specialty of cardiothoracic and vascular anesthesia. The first major theme is the commemoration of the sixtieth anniversary of the first successful cardiac surgical procedure with cardiopulmonary bypass conducted by Dr Gibbon. This major milestone revolutionized the practice of cardiovascular surgery and invigorated a paradigm of mechanical platforms for contemporary perioperative cardiovascular practice. Dr Kolff was also a leading contributor in this area because of his important contributions to the refinement of cardiopulmonary bypass and mechanical ventricular assistance. The second major theme is the diffusion of echocardiography throughout perioperative practice. There are now guidelines and training pathways to guide its generalization into everyday practice. The third major theme is the paradigm shift in perioperative fluid management. Recent large randomized trials suggest that fluids are drugs that require a precise prescription with respect to type, dose, and duration. The final theme is patient safety in the cardiac perioperative environment. A recent expert scientific statement has focused attention on this issue because most perioperative errors are preventable. It is likely that clinical research in this area will blossom because this is a major opportunity for improvement in our specialty. The patient care processes identified in these research highlights will further improve perioperative outcomes for our patients.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2010

The aortic valve treatment revolution continues with the maturation of aortic valve repair and the dissemination of transcatheter aortic valve implantation. The recent publication of comprehensive multidisciplinary guidelines for diseases of the thoracic aorta has assigned important roles for the cardiovascular anesthesiologist and perioperative echocardiographer. Although intense angiotensin blockade improves outcomes in heart failure, it might further complicate the maintenance of perioperative systemic vascular tone. Ultrafiltration as well as intensive medical management guided by the biomarker brain natriuretic peptide improves outcomes in heart failure. Continuous-flow left ventricular assist devices have further improved outcomes in the surgical management of heart failure. Major risk factors for bleeding in the setting of these devices include advanced liver disease and acquired von Willebrand syndrome. The metabolic modulator perhexiline improves myocardial diastolic energetics to achieve significant symptomatic improvement in hypertrophic cardiomyopathy. A landmark report was also published recently that outlines the major areas for future research and clinical innovation in this disease. Landmark trials have documented the outcome importance of perioperative cerebral oxygen saturation monitoring as well as the outcome advantages of the Sano shunt over the modified Blalock-Taussig shunt in the Norwood procedure. Furthermore, the development and evaluation of pediatric-specific ventricular assist devices likely will revolutionize the mechanical management of pediatric heart failure. A multidisciplinary review has highlighted the priorities for future perioperative trials in congenital heart disease. These pervasive developments likely will influence the future training models in pediatric cardiac anesthesia.