Lipoprotein(a) Fails to Steer Heart Attack Damage in Landmark MRI Study

When a heart attack strikes, cardiologists race to reopen the blocked coronary artery and restore blood flow to starving heart muscle. Yet the rescue itself carries a paradox: the return of oxygenated blood can inflict further damage on the very tissue it was meant to save, a phenomenon known as ischemia–reperfusion injury. For years, researchers have suspected that the fats circulating in a patient’s bloodstream might shape how badly the heart suffers during this violent transition from deprivation to restoration. Now, one of the most detailed investigations to date has delivered a surprising verdict on one of cardiology’s most talked-about lipids.

A team at the Medical University of Innsbruck, led by Magdalena Holzknecht and Martin Reindl, examined whether lipoprotein(a), a genetically determined particle increasingly flagged as an independent cardiovascular risk factor, influences the extent of myocardial and microvascular damage in patients suffering their first ST-elevation myocardial infarction, the most severe form of heart attack. The findings, published open access in Clinical Research in Cardiology, reveal a striking dissociation: while conventional LDL cholesterol was measurably linked to larger infarcts and more severe microvascular injury, lipoprotein(a) showed no meaningful association with any of these damage patterns, nor with medium-term clinical outcomes.

The study drew on the prospective MARINA-STEMI cohort, in which 518 patients with a median age of 59 years, 19 percent of them women, were treated with primary percutaneous coronary intervention between 2018 and 2024. All participants met strict criteria: a first STEMI confirmed by European and American cardiology committee standards, revascularization within twelve hours of symptom onset, and no prior myocardial infarction or coronary intervention. Blood drawn at coronary care unit admission allowed the researchers to quantify lipoprotein(a) using a particle-enhanced immunological turbidity test on a Roche cobas system, alongside total, LDL and HDL cholesterol. Median lipoprotein(a) at admission was 27 nmol/l, with an interquartile range of 20 to 90 nmol/l, while median LDL cholesterol stood at 141 mg/dl.

The real power of the investigation lay in its imaging. Every patient underwent multiparametric cardiovascular magnetic resonance on a 1.5-Tesla Siemens MAGNETOM Avanto fit scanner, first within the first week after PCI and again after four months. The standardized protocol combined high-resolution cine imaging with a voxel size of 1.5 by 1.5 by 6.0 millimeters to capture left ventricular volumes and ejection fraction, late gadolinium enhancement imaging roughly fifteen to twenty minutes after contrast administration to delineate infarct size, and T2* mapping performed before contrast to detect intramyocardial hemorrhage and persistent iron deposition in the infarct core. Infarct size, expressed as a percentage of total left ventricular myocardial mass, was quantified by identifying areas of hyperenhancement exceeding the signal intensity of remote myocardium by more than five standard deviations.

The baseline scan, performed at a median of four days after PCI, revealed a median infarct size of 14 percent of left ventricular myocardial mass. Intramyocardial hemorrhage, the hallmark of severe microvascular injury, was present in 33 percent of patients, and microvascular obstruction in 54 percent. By the four-month follow-up, infarct size had decreased to a median of 12 percent, hemorrhage persisted in 23 percent as iron deposition within the infarct core, and microvascular obstruction had largely resolved, affecting just 11 percent of patients. These tissue-level markers are considered the gold standard for gauging reperfusion injury and are strongly linked to both short- and long-term prognosis after STEMI.

Against this backdrop, the lipid comparisons produced a clear split. LDL cholesterol correlated significantly with infarct size both at baseline and at four months, with Spearman coefficients of 0.114 and 0.119 respectively, and patients with infarcts at or above the cohort median had higher LDL concentrations than those with smaller infarcts. LDL was also elevated in patients with intramyocardial hemorrhage, 145 versus 140 mg/dl, and in those with microvascular obstruction, 144 versus 138 mg/dl. Total cholesterol followed the same pattern. Lipoprotein(a), in contrast, showed no correlation with infarct size at either time point, no difference between patients with and without hemorrhage, 25 versus 28 nmol/l, and no association with microvascular obstruction or persistent iron deposition. Even when the researchers applied logistic regression and adjusted for ischemic time, an important determinant of large infarcts, the estimate for lipoprotein(a) remained essentially unchanged and statistically neutral.

The clinical endpoint reinforced the imaging story. Elevated lipoprotein(a), defined as 105 nmol/l or higher according to current guideline thresholds, was present in 22 percent of the cohort, 114 patients. Over a median follow-up of 21 months, 45 patients, roughly 9 percent, experienced a major adverse cardiovascular event, a composite of all-cause death, re-infarction, or new congestive heart failure, including 16 deaths, 16 re-infarctions and 13 heart failure events. The MACE rate was virtually identical in patients with and without elevated lipoprotein(a), 8.8 versus 8.7 percent, and Kaplan–Meier analysis of MACE-free survival showed no separation between the groups. Statin therapy, initiated in 99 percent of patients by discharge and maintained in 83 percent throughout follow-up, likewise showed no association with the exploratory clinical outcomes.

Why would a particle so firmly established as a lifetime risk factor for coronary artery disease fail to leave a fingerprint on the acute injury itself? The Innsbruck investigators point to a fundamental temporal distinction in how these lipids operate. LDL is a dynamic molecule directly embedded in the pathophysiology of the acute event: it drives lipid-rich plaque formation, raises thrombus burden with heightened risk of distal embolization, promotes endothelial oxidative stress, and contributes to the no-reflow phenomenon that starves the microcirculation after epicardial reperfusion. Lipoprotein(a), by contrast, may exert its pro-atherogenic and pro-inflammatory effects over decades, fueling chronic plaque development and instability through oxidized phospholipids that elicit arterial wall inflammation, rather than modulating the downstream myocardial damage once the artery has been reopened. In the context of timely reperfusion with primary PCI, the severity of tissue injury may be governed largely by total ischemic time, culprit vessel patency, reperfusion injury and individual microcirculatory susceptibility, factors that sit downstream of any individual’s lipoprotein(a) level.

The authors are careful to frame the conclusions within the study’s limits. The observational design precludes causal inference, the 9 percent event rate and limited follow-up may have reduced statistical power to detect subtle outcome differences, and the findings apply to stable STEMI patients suitable for CMR imaging rather than to delayed-reperfusion or non-STEMI populations. Women, at 19 percent of the cohort, remain underrepresented, a proportion consistent with previous CMR-based STEMI studies but still a caveat for generalizability. The clinical outcome analysis was explicitly exploratory and confined to the early post-infarction phase.

Nevertheless, the message for clinicians and researchers is consequential. Lipoprotein(a) should primarily be regarded as a risk-enhancing factor for the development of cardiovascular events, the authors conclude, rather than as a marker of infarct severity once STEMI has occurred. With potent lipoprotein(a)-lowering therapies, including antisense oligonucleotides and small interfering RNAs, now being tested in people with established cardiovascular disease, the study suggests these agents are unlikely to shrink infarcts or rescue the microcirculation in the acute setting, even as they may prove valuable for long-term prevention. For the 518 patients whose hearts were scanned in extraordinary detail, the fats that built their plaques over a lifetime told one story, while the damage inflicted in the hours around reperfusion told quite another.

Subject of Research: Cardiology

Article Title: Association of lipoprotein(a) with ischemia–reperfusion injury in patients with ST-elevation myocardial infarction

Article References: Holzknecht, M., Tiller, C., Lechner, I., Oberhollenzer, F., Kaser, A., Fischer, P., Sandor, A., Gollmann-Tepeköylü, C., Mayr, A., Bauer, A., Metzler, B., Reinstadler, S. J., & Reindl, M. (2026). Association of lipoprotein(a) with ischemia–reperfusion injury in patients with ST-elevation myocardial infarction. Clinical Research in Cardiology. https://doi.org/10.1007/s00392-026-03044-9

Image Credits: AI Generated

DOI: 10.1007/s00392-026-03044-9

Keywords: lipoprotein(a), STEMI, ischemia-reperfusion injury, cardiovascular magnetic resonance, LDL cholesterol, microvascular injury, myocardial infarction, Association, lipoprotein, ischemia, reperfusion, injury