Poverty Predicts Failed Heart Attack Clot-Busting in War-Torn Yemen, Study Finds

When a heart attack strikes, every minute of delay allows more heart muscle to die, and the treatment that follows must work quickly and reliably. In wealthy health systems, patients with ST-elevation myocardial infarction, the most dangerous form of heart attack, are usually rushed to a catheterization laboratory for primary percutaneous coronary intervention, a mechanical procedure that opens the blocked artery directly. In much of the world, however, that option simply does not exist. Instead, clinicians rely on thrombolytic drugs such as streptokinase, an inexpensive clot-dissolving enzyme that has been a workhorse of cardiology for decades. A new prospective study from Yemen, published in the International Journal for Equity in Health, now reveals a stark and troubling pattern: whether this life-saving drug actually works appears to depend, in part, on how much money a patient has.

The research, led by Tasneem Al-Namshah and colleagues at Sana’a University with collaborators at Al-Razi University, enrolled 216 patients diagnosed with STEMI who received streptokinase at a tertiary hospital in Sana’a between 2024 and 2025. Yemen, devastated by years of armed conflict, offers a rare and sobering window into how cardiovascular care functions when resources are scarce and infrastructure is shattered. The team assessed each patient’s socioeconomic status using a composite score adapted to the local context, capturing the realities of income, education, and living conditions in a country where conventional measures of wealth may not translate cleanly. Patients were then followed through their hospital stay to track whether the drug succeeded in reopening the infarct-related artery and how they fared clinically.

The technical definition of success was rigorous. Reperfusion failure was defined as failure to achieve at least 50 percent resolution of the elevated ST segments on the electrocardiogram at 90 minutes after thrombolysis, a standard surrogate indicating that the occluded coronary artery has not been adequately reopened and that myocardial tissue remains starved of blood. By this measure, the socioeconomic gradient was dramatic. Successful reperfusion was achieved in only 27.0 percent of patients in the low socioeconomic group, compared with 65.8 percent of those of intermediate status and 80.6 percent of high-status patients, a difference that was highly statistically significant. In other words, the poorest patients failed thrombolysis nearly three times as often as the wealthiest, and more than twice as often as those in the middle tier.

Part of the explanation lies in time. The study documented that low-socioeconomic-status patients arrived at the hospital far later after symptom onset, with a median symptom-to-door time of 360 minutes compared with 240 minutes for their higher-status counterparts, a difference that was statistically significant. Total ischemic times, which encompass the entire duration from the first symptom to reperfusion, followed the same pattern at 434 versus 330 minutes. This matters because thrombolytic efficacy is strongly time-dependent: the longer a clot has matured and the more myocardium has been jeopardized, the less likely fibrinolysis is to achieve complete and sustained reperfusion. Six hours of delay, as seen in the poorest group, pushes patients well beyond the window in which streptokinase performs optimally.

The downstream clinical consequences were equally stark. In-hospital mortality climbed along the socioeconomic gradient, from zero percent among high-status patients to 0.9 percent in the intermediate group and 6.8 percent among the poorest. Major adverse cardiovascular events, a composite endpoint typically encompassing death, reinfarction, and other serious cardiac complications, affected 18.9 percent of low-status patients versus 9.9 percent of intermediate and 6.5 percent of high-status patients. Both gradients were statistically significant, painting a coherent picture in which poverty was associated not only with failed reperfusion but with worse survival and more complications during the same hospital admission.

Crucially, the investigators did not stop at simple associations. They employed multivariable logistic regression, adjusting for potential confounders, and found that low socioeconomic status remained independently associated with markedly higher odds of reperfusion failure, with an odds ratio of 16.19 and a 95 percent confidence interval of 4.92 to 53.29. To probe the robustness of this finding against unmeasured confounding, the team calculated an E-value, a quantitative sensitivity metric indicating how strong an unmeasured factor would need to be to explain away the observed association. The E-value of 31.88 is extraordinarily high, suggesting that no plausible unmeasured variable, short of an implausibly powerful one, could plausibly account for the entire effect. This analytical rigor strengthens the argument that the socioeconomic gradient reflects a genuine causal pathway rather than statistical artifact.

One particularly informative finding concerns what did not differ. Rates of post-thrombolysis percutaneous coronary intervention, the rescue or adjunctive procedure performed after clot-dissolving drugs, were similar across socioeconomic groups. This suggests that the disparity was not driven by unequal access to mechanical revascularization once patients were inside the hospital. Instead, the damage appears to be done before patients ever reach the hospital doors, in the hours lost to delayed recognition of symptoms, lack of transportation, financial barriers to seeking care, and the logistical chaos of a conflict zone. The authors argue that context-appropriate interventions, including subsidized emergency transport and pharmaco-invasive networks that link thrombolysis in peripheral settings to timely angiography, are essential to mitigate these prehospital delays and promote equitable STEMI care.

The Yemeni findings resonate with a broader literature linking socioeconomic position to cardiovascular outcomes, but they sharpen the picture in an important way. Most prior studies have examined disparities in access to advanced procedures or in long-term outcomes shaped by secondary prevention and rehabilitation. This study isolates a more fundamental inequity: the biological efficacy of the initial reperfusion therapy itself. If the clot-dissolving drug fails more often in poor patients largely because they arrive later, then the intervention point is prehospital, encompassing public awareness of heart attack symptoms, affordable and rapid transport, and streamlined triage. In a conflict-affected setting where ambulances are scarce, fuel is expensive, and roads are dangerous, each of these steps becomes a formidable barrier for families with the fewest resources.

The study does carry limitations inherent to its design and setting. As a single-center prospective observational study of 216 patients, its findings require replication in other conflict-affected and resource-limited environments before broad generalization. The composite socioeconomic score, while context-adapted, cannot capture every dimension of disadvantage, and observational designs can never fully exclude residual confounding, however reassuring the E-value may be. Streptokinase itself is an older thrombolytic with known limitations, including antigenicity and a relatively high failure rate even under ideal circumstances, which may have amplified the observed gradients. Nevertheless, the internal consistency of the data, spanning delay times, reperfusion success, mortality, and composite adverse events, lends the conclusions considerable weight.

For global health, the message is uncomfortable but clear. Cardiovascular disease is no longer a affliction confined to wealthy nations, and the tools available to poorer countries must be made to work for everyone within them. Streptokinase costs only a few dollars per dose, yet its effectiveness in Yemen appears to be rationed by circumstance as much as by biology. The authors’ call for subsidized emergency transport and pharmaco-invasive networks represents a pragmatic, achievable agenda: rather than waiting for catheterization laboratories that may take decades to build, health systems can invest in the unglamorous logistics of getting patients through the door faster and connecting fibrinolysis to follow-up angiography. In a world where conflict and poverty increasingly shape disease outcomes, this study demonstrates that the fight for health equity begins not in the operating theater but on the road to the hospital.

Subject of Research: Socioeconomic disparities in thrombolytic reperfusion success and outcomes after ST-elevation myocardial infarction in conflict-affected Yemen

Article Title: Association of socioeconomic status with streptokinase reperfusion failure and in-hospital outcomes in STEMI: evidence from conflict-affected Yemen

Article References: Al-Namshah, T., Al-Kebsi, M., Alradi, A., Al-Habeet, A., Al-Motarreb, A., Al-Wather, N., Alodhari, R., & Al-Jalal, A. (2026). Association of socioeconomic status with streptokinase reperfusion failure and in-hospital outcomes in STEMI: evidence from conflict-affected Yemen. International Journal for Equity in Health. https://doi.org/10.1186/s12939-026-03047-y

Image Credits: AI Generated

DOI: 10.1186/s12939-026-03047-y

Keywords: socioeconomic status, STEMI, streptokinase, reperfusion failure, Yemen, thrombolysis, health equity, conflict-affected settings, in-hospital mortality, MACE, prehospital delay, cardiovascular outcomes