21 A comparison of coronary haemodynamics in 40cc versus 50cc intra-aortic balloon pumps
Bibliographic record
Abstract
Introduction Randomised trials have questioned the benefit of intra-aortic balloon pump (IABP) counterpulsation in high-risk PCI and shock. A larger capacity balloon has been introduced into routine clinical practice that has been shown to provide greater systolic unloading and diastolic augmentation compared with the standard balloon. Our aim was to investigate whether larger capacity balloons provide a greater augmentation in coronary flow compared with standard capacity balloons. Methods Seven patients with severe ischaemic cardiomyopathy were studied using a two-treatment, single sequence crossover protocol at the time of elective percutaneous coronary intervention (PCI). Simultaneous coronary pressure and Doppler measurements were undertaken in the target vessel after PCI using a Volcano Combowire, during unassisted and assisted IABP conditions, first with a 40cc IABP and then, five minutes later, with a 50cc IABP. Measurements were taken with intact autoregulation and with autoregulation temporarily disabled by administration of intracoronary adenosine. Coronary wave intensity analysis was performed to characterise the wave energies associated with balloon counterpulsation. Data are presented as mean ± SD. Results Patients were 65 (±12) years old (75% male). Left ventricular ejection fraction was 29% (±11%) with a coronary jeopardy score of 11 (±2) (maximum possible score=12). There was no difference between the 40cc and 50cc IABP balloons in average peak velocity (50.3±33.6 vs. 49.7±24.2 cm s −1 p=0.916), mean distal coronary pressure (83.4±16 vs. 85.2±20 mmHg, p=0.549) (see Figure 1), or microvascular resistance (181.6±52.9 vs. 207.5±83.4 mmHgcm −1 s, p=0.218) when autoregulation was disabled. Results were similar during basal assisted conditions. On wave intensity analysis, a late diastolic forward compression wave was identified during IABP support that was not seen during unassisted conditions. The magnitude of the IABP-forward compression wave was numerically greater with the 50cc balloon during basal conditions, which did not reach statistical significance (1.7±1.7 vs. 2.8±3.1, W m −2 s −2 × 10 5 , p=0.155) (see Figure 2). Conclusions The larger capacity balloon does not provide greater augmentation in coronary flow or reduction in microvascular resistance compared with the standard balloon during basal or hyperaemic conditions. We did not measure left ventricular afterload or myocardial oxygen demand in this study and cannot exclude a differential effect of the 50cc balloon on myocardial oxygen supply and demand. Abstract 21 Figure 1 Box plots demonstrating effects of 40cc and 50cc balloons on average peak velocity (A) and mean distal coronary pressure (B). Abstract 21 Figure 2 (A) Wave Intensity Profile during intra-aortic balloon pump assisted conditions, highlighting the temporally related wave energies with device inflation (IABP-FCW) and deflation (IABP-FEW). FCW=forward compression wave; BCW= backward compression wave; FEW=forward expansion wave, BEW= backward expansion wave. (B) Box plot demonstrating effects of 40cc and 50cc balloons on IABP-FCW during basal conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".