Researchers Explore Novel Unloading Strategy in AMI – EMJ

ACUTE myocardial infarction patients may benefit from a novel method of left ventricular unloading, using an iatrogenic atrial septal defect (iASD), according to new computational and animal model data. 

Primary unloading of the left ventricle has been proposed as an effective strategy to reduce infarct size and lower the risk of subsequent heart failure following acute myocardial infarction (AMI). 

However, current mechanical unloading approaches can often be associated with procedural complexity, complications, and high cost. 

Iatrogenic Atrial Septal Defect Reduced Left Sided Pressure 

To explore an alternative, researchers evaluated the haemodynamic effects of creating an iASD using both a cardiovascular computer simulation and a swine model of AMI. 

The computer model incorporated pre-revascularisation haemodynamic data from 79 patients with acute AMI.  

Simulated defects ranging from 2.5–12.5 mm were assessed.  

Across all defect sizes, pulmonary capillary wedge pressure declined significantly (21.2±8.3 mmHg) compared with baseline (13.2±4.2 mmHg).  

The greatest unloading effect appeared to plateau at a defect size of 7.5 mm, with no significant additional reduction in pressure observed with larger defects.  

Swine Model Supports Haemodynamic Feasibility 

Investigators then tested the 7.5 mm defect size in three adult swine with experimentally induced AMI.  

A total of 60 haemodynamic measurements were collected during baseline conditions, coronary artery occlusion, and iASD opening and closure cycles.  

Coronary obstruction increased pulmonary capillary wedge pressure from 14.72±1.60 mmHg to 21.95±3.94 mmHg.  

Following creation of the defect, pulmonary capillary wedge pressure fell significantly to 17.10±2.73 mmHg.  

Researchers reported that pressures approached baseline values after unloading.  

No Immediate Haemodynamic Compromise Observed 

Importantly, researchers reported that the iASD intervention did not appear to adversely affect key measures of systemic haemodynamic stability.  

Mean arterial pressure showed no significant reduction after creation of the defect (43.67±13.51 mmHg) compared with coronary obstruction alone (48.32±12.09 mmHg). 

Similarly, cardiac output remained unchanged; 2.68±0.50 L/min versus 2.37±0.22 L/min. Pulmonary pressures also remained stable following the procedure. 

While larger studies and longer-term assessments are required, the findings support further evaluation of this approach as a potentially simple and cost-effective unloading strategy for patients with AMI. 

Reference 

Aliev E et al. Assessing iatrogenic atrial septal defect as a primary unloading strategy in acute myocardial infarction using computational and swine model. Sci Rep. 2026;DOI:10.1038/s41598-026-56427-3 

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