Reduced-Dose Thrombolysis in Acute Pulmonary Embolism A Systematic Review.

Pulmonary embolism (PE) is the third-leading cause of cardiovascular mortality and the second-leading cause of death in cancer patients. The clinical efficacy of thrombolysis for acute PE has been proven, yet the therapeutic window seems narrow, and the optimal dosing for pharmaceutical reperfusion therapy has not been established. Higher doses of systemic thrombolysis inevitably associated with an incremental increase in major bleeding risk. To date, there is no high-quality evidence regarding dosing and infusion rates of thrombolytic agents to treat acute PE. Most clinical trials have focused on thrombolysis compared with anticoagulation alone, but dose-finding studies are lacking. Evidence is now emerging that lower-dose thrombolytic administered through a peripheral vein is efficacious in accelerating thrombolysis in the central pulmonary artery and preventing acute right heart failure, with reduced risk for major bleeding. The present review will systematically summarize the current evidence of low-dose thrombolysis in acute PE.

Low-Dose Alteplase versus Conventional Anticoagulation to treat Submassive Pulmonary Embolism in Hispanic Patients.

The use of low-dose tissue plasminogen activator (tPA) in Hispanic patients with submassive pulmonary embolism (PE) is understudied. The purpose of this study is to explore the use of low-dose tPA in Hispanic patients with submissive PE compared with counterparts that received heparin alone. We retrospectively analyzed a single-center registry of patients with acute PE between 2016 and 2022. Out of 72 patients admitted for acute PE and cor pulmonale, we identified six patients that were treated with conventional anticoagulation (heparin alone) and six patients who received low-dose tPA (and heparin afterward). We analyzed if low-dose tPA was associated with differences in length of stay (LOS) and bleeding complications. Both groups were similar in regard to age, gender, and PE severity (based on Pulmonary Embolism Severity Index scores). Mean total LOS for the low-dose tPA group was 5.3 days, compared with 7.3 days in the heparin group ( p = 0.29). Mean intensive care unit (ICU) LOS for the low-dose tPA group was 1.3 days compared with 3 days in the heparin group ( p = 0.035). There were no clinically relevant bleeding complications documented in either the heparin or the low-dose tPA group. Low-dose tPA for submassive PE in Hispanic patients was associated with a shorter ICU LOS without a significant increase in bleeding risk. Low-dose tPA appears to be a reasonable treatment option in Hispanic patients with submassive PE who are not at high bleeding risk (<5%).

Impact and predictors of noncircular left ventricular outflow tract shapes on estimating aortic stenosis severity by means of continuity equations.

Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined. In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area. We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm(2)) was underestimated by the standard method (1.05 ± 0.47 cm(2); P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape. More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.

Impact of valvular calcification on the diagnostic accuracy of transesophageal echocardiography for the detection of congenital aortic valve malformation.

BACKGROUND: Degeneration of congenital bicuspid or unicuspid aortic valves can progress more rapidly than that of tricuspid valves, and an early diagnosis significantly impacts decision making and outcome. We hypothesized that the extent of valvular calcification would negatively influence the diagnostic accuracy of multiplane transesophageal echocardiography (TEE) for the diagnosis of congenital aortic valve disease. METHODS: TEE was performed in 57 patients undergoing aortic valve replacement surgery for aortic stenosis (n = 46), pure regurgitation (n = 9), or significant regurgitation with less than severe aortic stenosis (n = 2). The degree of aortic valve calcification and the number of valve cusps were determined at surgery. RESULTS: Surgical inspection confirmed 14 bicuspid and 43 tricuspid aortic valves. Sensitivity and specificity of TEE for the diagnosis of congenital aortic valve malformation was 93% (13/14) and 91% (39/43) (P = 0.0001), respectively. In patients with no or mild aortic valve calcification (n = 13), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 100% (5/5) and 100% (8/8) (P = 0.001), respectively. In patients with moderate or marked aortic valve calcification (n = 44), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 89% (8/9) and 89% (31/35) (P<0.0001), respectively. In this subgroup of 44 patients, there were four false-positive and one false-negative diagnoses due to valvular calcification. CONCLUSIONS: Although TEE is highly sensitive and specific for the detection of congenital aortic valve malformations, presence of moderate or marked calcification of the aortic valve may result in false positive and false negative diagnoses.

Recipient atrial flutter masquerading as donor flutter in a heart transplant recipient.

Atrial flutter is common after orthotopic heart transplantation. We present the case of a patient who presented with atrial flutter on 12-lead electrocardiogram. On invasive electrophysiologic study, the donor heart was found to be in sinus rhythm and the recipient atrium was in flutter, which was dissociated from the donor.

Renal hemodynamics: theory and practical tips.

The angiographic assessment of renal artery stenosis (RAS) is often difficult and not reliable. A hyperemic systolic pressure gradient (HSPG) >20 mm Hg provides the highest concordance rate of 100% with an intravascular ultrasound (IVUS) minimal lumen cross sectional area <8.6 mm(2) to predict the severity of RAS. We present 4 cases in whom the role of HSPG and IVUS compared with angiography for the assessment of the severity of RAS is discussed.

Hypotension during dobutamine stress transesophageal echocardiography: relationship with provoked left ventricular obstruction.

BACKGROUND: The mechanism of hypotension during dobutamine stress (DS) echocardiography is unknown. The role of left ventricular outflow tract (OT) or midcavitary (MID) obstruction provoked during stress in this process remains controversial. We hypothesized that left ventricular OT obstruction would account for hypotension as opposed to MID obstruction. METHODS: Multiplane DS transesophageal echocardiography (TEE) was performed in 142 adult patients who displayed no resting obstruction or DS-provoked ischemia. TEE was used to identify the precise site of obstruction. Dobutamine was infused from 5 to 40 microg/kg/min and atropine as needed. Continuous wave Doppler was performed from appropriate views to assess for obstruction. RESULTS: Ventricular obstruction was provoked at the OT in 13 patients, MID in 10 patients, and at both sites in 4 patients. A total of 115 patients without dobutamine-induced obstruction served as control subjects. Systolic blood pressure at rest was similar in all groups, but decreased to a greater magnitude from rest to peak stress in the OT (-20 +/- 40 mm Hg) and MID (-29 +/- 38 mm Hg) groups as compared with the control group (8 +/- 30 mm Hg). A hypotensive response (ie, decrease in systolic blood pressure > or = 20 mm Hg from baseline to peak stress) was significantly greater in OT (69%, P = .001) and MID (60%, P < .05) groups as compared with the control group (19%). Heart rate and ejection fraction at rest or peak did not differ among groups. Among clinical and hemodynamic variables, left ventricular OT (relative risk 5.9; 95% confidence interval 1.9-18; P < .002) and MID (relative risk 3.6; 95% confidence interval 1.1-12; P < .05) obstructions were the only predictors for a hypotensive response. CONCLUSIONS: Hypotension during DS TEE occurs commonly when ventricular obstruction is provoked. These data support a causal relationship between a provoked ventricular obstruction and hypotension during DS TEE.

Safety of dobutamine stress transesophageal echocardiography in obese patients for evaluation of potential ischemic heart disease.

The purpose of this study was to determine the safety of dobutamine stress transesophageal echocardiography (DS-TEE) in the evaluation of potential coronary artery disease in obese patients. Obese patients tend to have a higher prevalence of hypertension, coronary artery disease, and sleep apnea conditions that could potentially predispose to complications during endoscopic procedures such as DS-TEE. In addition, obese patients are more likely to have oxygen desaturation during upper gastrointestinal endoscopy. Thus, the safety of DS-TEE in 90 obese patients (body mass index (BMI) > or = 27.5 kg/m2) and 86 nonobese patients (BMI < 27.5 kg/m2) was compared. Minor complications (i.e., complications of transient duration and requiring no or only simple intervention) occurred with almost equal frequency in the nonobese and obese groups (28% vs. 29%, P = ns). Transient hypotension was observed in 9% of the obese group compared to 22% in the nonobese group (P < 0.025). However, transient hypertension was noted in 20% of the obese patients compared to 6% in the nonobese group (P < 0.01). A major complication occurred in three obese patients (3.3%), which included hypotension, marked elevation of systolic blood pressure, or ventricular fibrillation. Four patients (4.7%, P = ns) of the nonobese group had a major complication, which included sustained ventricular tachycardia in one, hypertension in one, and hypotension in two patients. No deaths occurred in either group. Although obesity should remain a consideration in the risk assessment of whether or not to perform DS-TEE, when proper precautions are instituted DS-TEE appears equally safe in obese as compared to nonobese patients.