Left-Sided Heart Failure

We included all patients who underwent coronary angiography with the primary indication of HF corresponding to International Classification of Diseases (ICD) 10th revision codes I50.1 (left ventricular failure), I50.2 [systolic (congestive) HF], I50.4 [combined systolic (congestive) and diastolic (congestive) HF], or I50.9 (HF, unspecified) and that showed concomitant MVD (coronary artery stenosis >50% in ≥2 vessels or left main) between 1 January 2000 and 31 March 2018. No patient was hospitalized for acute coronary syndrome (i.e. ST-elevation or non-ST-elevation myocardial infarction) within the 6 months before the index coronary angiography. All patients were included in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) and Swedish Register of Information and Knowledge about Swedish Heart Intensive Care Admissions (RIKS-HIA), which are part of the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) registry and was established in 1992. Swedish Coronary Angiography and Angioplasty Registry provides a web-based platform dedicated to data collection from all angiographies and PCIs performed in coronary catheterization laboratories (n = 31) in Sweden (https://www.ucr.uu.se/swedeheart/). Each catheterization procedure is described with ∼50 angiographic and 200 PCI, demographic- and procedure-related variables. The registry is financed by the county councils in Sweden and the Swedish state and provides ∼100% procedure coverage in Sweden. To obtain information about vital status of the patients, the SCAAR database is continuously merged with the national population registry. More detailed information about SCAAR’s organization has been published elsewhere.^10–14 (link) The study was approved by the ethics committee at the University of Gothenburg (Dnr. 759-13, date of approval 6 May 2014).

Client‐owned dogs that were clinically healthy or had MMVD were prospectively included in our study. Dogs were diagnosed as clinically healthy based on medical history, physical examination, electrocardiography, radiography, noninvasive blood pressure measurement, and transthoracic echocardiography. Dogs were diagnosed as having MMVD based on the presence of mitral valve thickening or prolapse and mitral regurgitation, as identified using transthoracic echocardiography.²⁵ If dogs with MMVD also had tricuspid regurgitation (TR), they were deemed as having PH according to TR ≥3.0 m/s (TR pressure gradient [TRPG] ≥36 mmHg). Dogs that had other cardiac diseases, diseases that might affect the cardiac function or pulmonary artery pressure (eg, respiratory disease, thromboembolic disease, heartworm disease, neoplastic disease, endocrine disease), and systemic hypertension (systolic blood pressure ≥160 mmHg)²⁶ were excluded from the study along with cases that had missing data.
Dogs with MMVD were divided into 3 groups based on the American College of Veterinary Internal Medicine consensus: stage B1 consisted of asymptomatic dogs with no or minimal remodeling, stage B2 consisted of asymptomatic dogs with substantial remodeling based on radiography and echocardiography, and stage C/D consisted of symptomatic dogs with current or past clinical signs of heart failure caused by MMVD.²⁷ In addition, dogs with MMVD were classified into 4 groups based on TRPG: non‐PH, defined as TRPG <36 mmHg or absence of TR; mild PH, defined as TRPG of 36 to 50 mmHg; moderate PH, defined as TRPG of 50 to 75 mmHg; and severe PH, defined as TRPG >75 mmHg.⁵, ¹² Furthermore, dogs with TR were classified qualitatively according to TR severity using color Doppler and continuous wave Doppler methods: mild TR consisted of dogs with a small TR jet based on color Doppler and a faint parabolic TR jet signal based on the continuous wave Doppler; moderate TR consisted of those with an intermediate TR jet and a dense parabolic TR jet signal; and severe TR consisted of those with a substantial large central or eccentric wall‐impinging TR jet and a dense triangular, early‐peaking TR jet signal.²⁸, ²⁹ Dogs were diagnosed as having left‐sided congestive heart failure if they had at least 1 clinical sign, such as tachypnea, respiratory distress, or exercise intolerance, supported by radiographic and ultrasonographic evidence of pulmonary venous congestion and pulmonary edema. Dogs were diagnosed as having R‐CHF if they had at least 1 radiographic and ultrasonographic finding indicative of ascites, pleural effusion or pericardial effusion or clinical signs of cardiac syncope, jugular venous congestion, or peripheral edema without any evidence of diseases except for PH, other than neurological diseases.