Impact of chronic advanced aortic regurgitation on the perioperative outcome of noncardiac surgery

Preoperative evaluation and perioperative management of patients undergoing major vascular surgery

Patients undergoing major vascular surgery have an increased risk of perioperative major adverse cardiovascular events (MACE). Accordingly, in this population, it is of particular importance to appropriately risk stratify patients' risk for these complications and optimize risk factors prior to surgical intervention. Comorbidities that portend a higher risk of perioperative MACE include coronary artery disease, heart failure, left-sided valvular heart disease, and significant arrhythmic burden. In this review, we provide a current approach to risk stratification prior to major vascular surgery and describe the strengths and weaknesses of different cardiac risk indices; discuss the role of noninvasive and invasive cardiac testing; and review perioperative pharmacotherapies.

Predictors of heart failure and all-cause mortality in asymptomatic patients with moderate and severe aortic regurgitation

BACKGROUND

Class I indications for aortic valve replacement (AVR) for severe chronic aortic regurgitation (AR) include AR attributable symptoms or left ventricular (LV) ejection fraction <50%. As noninvasive estimates of elevated LV filling pressures (LVFP's) have been noted to predict heart failure (HF) readmission and all-cause mortality (ACM) in HF patients, we hypothesize that elevated LVFP's may also be independent predictors of HF and ACM in chronic AR.

METHODS

We developed a single center patient database of moderate or greater AR diagnoses between 2003 and 2008 and followed each patient through January 2013. We included patients with >30 days follow-up with interpretable Doppler-echocardiograms. We recorded demographic variables, EuroScore II, incident HF and ACM, and Doppler-echo variables of LV size, systolic and diastolic function.

RESULTS

Patients with severe AR (105 patients) and moderate AR (201 patients) had similar EuroScore II values and similar incident HF and ACM. For the 180 patients who developed HF, effective arterial elastance (aHR = 1.70 (1.01-2.83), p = .041), LV end-diastolic dimension (aHR = 1.83, (1.11-3.03), p = .0176), E/e' (aHR = 3.04, (1.83-5.05), p < .0001), eccentric hypertrophy (EH) (aHR = 2.39, (1.62-5.12), p = .0004), and tricuspid regurgitation (TR) velocity (aHR = 5.75, (3.70-10.36), p < .0001) were independent predictors. For the 118 patients with ACM, EH (aHR = 1.73, (1.02-3.28), p = .0414), systolic blood pressure (aHR = .58, (.33-.95), p = .0301), left atrial volume index (aHR = 1.82, (1.06-3.06), p = .0293), E/e' (aHR = 1.83, (1.07-3.08), p = .0280), and TR velocity (aHR = 4.14, (2.22-6.49), p < .0001) were independent predictors.

CONCLUSIONS

Elevated TR velocity and EH were strong markers of HF and ACM in patients with asymptomatic severe AR and in moderate AR.

Non-cardiac surgery in patients with valvular heart disease

In patients with significant valvular heart disease (VHD) undergoing non-cardiac surgery (NCS), perioperative adverse cardiac events are a relevant issue. Although postoperative outcomes can be adversely affected by valve-related haemodynamic instability, recommended perioperative risk scores prioritise the risk of the surgical procedure and the presence of cardiovascular risk factors, neglecting the presence or extent of VHD. Perioperative management and anaesthetic approach should focus on the underlying type and severity of VHD, the compensatory mechanisms deployed by left ventricle and right ventricle and the type and risk of NCS. Due to the lack of randomised trials investigating different therapeutic approaches of valvular intervention prior to NCS, recommendations mainly rely on consensus opinion and inference based on large observational registries. As a general rule, valvular intervention is recommended prior to NCS in symptomatic patients or in those who meet standard criteria for cardiac intervention. In the absence of such conditions, it is reasonable to perform NCS with tailored anaesthetic management and close invasive perioperative haemodynamic monitoring. However, patient-specific management strategies should be discussed with the heart team preoperatively. Symptomatic patients with severe VHD or those undergoing high-risk NCS should ideally be treated at a high-volume medical centre that is equipped to manage haemodynamically complex patients during the perioperative period.

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

Application of transthoracic echocardiography in patients receiving intermediate- or high-risk noncardiac surgery

Background

Cardiovascular events are the leading cause of perioperative complications among patients undergoing noncardiac surgery. However, the role of echocardiography for preoperative cardiac risk stratification prior to major noncardiac surgery is still controversial.

Methods

This retrospective study included a total of 1453 patients (51% male; age, 67 ± 16) who underwent intermediate- or high-risk major abdominal surgery or orthopedic surgery at two medical centers in South Taiwan between February 2013 and June 2016. All patients underwent preoperative transthoracic echocardiography (TTE). All of the included patients were followed up for 56 days after surgery. The primary endpoints were major adverse events (MAEs), i.e., all-cause mortality and major adverse cardiovascular-cerebral events (MACCEs).

Results

A total of 35 patients (2.4%) reached the primary endpoint: 24 patients (1.6%) died, and 17 patients (1.2%) had MACCEs. Patients with postsurgery MAEs had higher average E/e’ values, a lower Left ventricular (LV) ejection fraction, and higher prevalence of significant mitral regurgitation (MR) and moderate-advanced chronic kidney disease (CKD). Multivariate analysis showed that the modified Lee index and significant MR were independent prognostic predictors of MAEs.

Conclusion

Preoperative identification of significant MR on TTE is associated with increased MAEs at 56 days compared with that predicted by the modified Lee index alone in patients undergoing intermediate- or high-risk noncardiac surgery.

Cardiac Screening in the Noncardiac Surgery Patient

This article will address common cardiac conditions that require evaluation prior to noncardiac surgery, characterization of urgency and the risk associated with surgical procedures, calculation of preoperative risk assessment, indications for diagnostic testing to quantify cardiac risk, and perioperative strategies to minimize the risk of cardiac complications.

Cardiac Evaluation and Monitoring of Patients Undergoing Noncardiac Surgery

Surgical management of disease has a tremendous impact on our health system. Millions of people worldwide undergo surgeries every year. Cardiovascular complications in the perioperative period are one of the most common events leading to increased morbidity and mortality. Although such events are very small in number, they are associated with a high mortality rate making it essential for physicians to understand the importance of perioperative cardiovascular risk assessment and evaluation. Its involves a detailed process of history taking, patient's medical profile, medications being used, functional status of the patient, and knowledge about the surgical procedure and its inherent risks. Different risk assessment tools and calculators have also been developed to aid in this process, each with their own advantages and limitations. After such a comprehensive evaluation, a physician will be able to provide a risk assessment or it may all lead to further testing if it is believed that a change in management after such testing will help to reduce perioperative morbidity and mortality. There is extensive literature on the significance of multiple perioperative testing modalities and how they can change management. The purpose of our review is to provide a concise but comprehensive analysis on all such aspects of perioperative cardiovascular risk assessment for noncardiac surgeries and provide a basic methodology toward such assessment and decision making.

The Preoperative Patient With a Systolic Murmur

Context:

Patients with undifferentiated systolic murmurs present commonly during the perioperative period. Traditional bedside assessment and auscultation has not changed significantly in almost 200 years and relies on interpreting indirect acoustic events as a means of evaluating underlying cardiac pathology. This is notoriously inaccurate, even in expert cardiology hands, since many different valvular and cardiac diseases present with a similar auditory signal.

Evidence Acquisition:

The data on systolic murmurs, physical examination, perioperative valvular disease in the setting of non-cardiac surgery is reviewed.

Results:

Significant valvular heart disease increases perioperative risk in major non-cardiac surgery and increases long term patient morbidity and mortality. We propose a more modern approach to physical examination that incorporates the use of focused echocardiography to allow direct visualization of cardiac structure and function. This improves the diagnostic accuracy of clinical assessment, allows rational planning of surgery and anaesthesia technique, risk stratification, postoperative monitoring and appropriate referral to physicians and cardiologists.

Conclusions:

With a thorough preoperative assessment incorporating focused echocardiography, anaesthetists are in the unique position to enhance their role as perioperative physicians and influence short and long term outcomes of their patients.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.