More than half of all patients receiving lifesaving cellular therapies develop a dangerous drop in blood pressure upon standing within their first month of treatment, according to one of the largest investigations of its kind. The condition, known as orthostatic hypotension, occurs when the cardiovascular system fails to compensate for the simple act of rising from a lying or seated position. In a retrospective analysis of 297 patients treated at Penn State Health Milton S. Hershey Medical Center, researchers found that the cumulative incidence of orthostatic hypotension reached 57.6 percent by day 30 after cell infusion, with a median onset of just five days. Perhaps more striking, roughly one in five patients experienced symptoms severe enough to notice, including nausea, fatigue, dizziness, palpitations, and headache. The findings, published in Supportive Care in Cancer, suggest that a routinely overlooked complication may be far more common in modern cancer care than clinicians have appreciated.
Orthostatic hypotension is classically defined as a decrease in systolic blood pressure of at least 20 millimeters of mercury, or a decrease in diastolic pressure of at least 10 millimeters of mercury, upon standing. In healthy people, standing triggers an almost instantaneous cascade of physiological responses: baroreceptors in the carotid arteries and aortic arch sense the pooling of blood in the legs and abdomen, prompting a reflexive increase in heart rate and constriction of blood vessels to maintain cerebral perfusion. When this autonomic compensation falters, the brain is briefly starved of oxygenated blood, producing lightheadedness, visual dimming, or in severe cases, fainting. While some patients remain entirely asymptomatic despite meeting the diagnostic criteria, others report fatigue, difficulty concentrating, or neck discomfort. In the general population, the condition is associated with falls, substantial morbidity, and even increased mortality, making its presence in vulnerable cancer patients a genuine safety concern.
The study cohort comprised 153 patients undergoing autologous hematopoietic cell transplantation, 127 receiving allogeneic transplants, and 17 treated with chimeric antigen receptor T-cell, or CAR-T, therapy. Blood pressure and heart rate were measured while patients lay supine and again at one and three minutes after standing, following institutional protocol. When the researchers stratified results by therapy type, the cumulative incidence of any orthostatic hypotension at day 30 was 62.8 percent in the autologous group, 52.0 percent in the allogeneic group, and 52.9 percent in the CAR-T group, a difference that did not reach statistical significance. However, the timing of onset varied subtly between groups. CAR-T patients tended to develop the condition earliest, with a median onset of day one, compared with day four in allogeneic recipients and day five in autologous transplant patients. Symptomatic disease was significantly more frequent in the autologous group, affecting 28.8 percent, compared with 15.7 percent of allogeneic patients and 5.9 percent of CAR-T recipients.
The early onset in CAR-T patients offers a tantalizing clue about underlying biology. CAR-T therapy works by engineering a patient’s own T cells to attack cancer, but the treatment frequently unleashes a flood of inflammatory signaling molecules known as cytokines. These molecules can drive hypotension by increasing the permeability of blood vessel walls, allowing fluid to leak out of the circulation and reducing the effective circulating blood volume. Elevated levels of cytokines such as interleukin-6, tumor necrosis factor-alpha, and transforming growth factor-alpha, which are common in patients with advanced malignancy, have also been correlated with disrupted circadian regulation and cortisol rhythms, implying impaired autonomic control of the cardiovascular system. In transplant patients, additional mechanisms come into play, including chemotherapy-induced gastrointestinal mucositis, nausea, and reduced oral intake, all of which deplete intravascular volume, alongside diarrhea, electrolyte disturbances, and medications with autonomic side effects.
Perhaps the most provocative finding concerned the care setting. Among patients with plasma cell disorders who underwent autologous transplantation, the researchers compared 96 inpatients with 19 outpatients treated more recently. The incidence of orthostatic hypotension was dramatically higher in the outpatient group, reaching 94.7 percent by day 30 compared with 54.2 percent among hospitalized patients, and onset occurred significantly earlier, at a median of day four versus day six. For symptomatic disease, the gap was even wider: 63.2 percent of outpatients versus 22.9 percent of inpatients. In multivariate analysis, outpatient treatment emerged as the strongest risk factor, carrying a hazard ratio of 3.60 for any orthostatic hypotension and 4.66 for the symptomatic form. The authors suggest this may reflect less fluid intake and poorer nutritional status on the patient side, combined with less intensive monitoring and fluid management on the provider side, though they caution that the small outpatient sample and differences in blood pressure monitoring may partly explain the disparity.
Beyond care setting, the analysis identified several other independent risk factors. A documented history of orthostatic hypotension before cellular therapy increased the risk of developing the condition again, with a hazard ratio of 1.76. For symptomatic disease, weight loss exceeding 2 percent from baseline roughly doubled the risk, with a hazard ratio of 2.09, while the occurrence of any infection within the first 30 days raised the risk by a factor of 2.57. The infection finding is particularly novel; the authors report that this is the first study to describe infection as a potential risk factor for orthostatic hypotension in the cancer population, with neutropenic fever being the most frequent infectious event in the cohort. Infections can precipitate distributive hypovolemia and vasodilation, undermining the very mechanisms the body relies upon to maintain blood pressure when standing. The weight loss threshold of 2 percent was chosen because losses of that magnitude are generally recognized as an indicator of dehydration.
Intriguingly, the analysis produced one result that runs counter to established expectations. Older patients, defined as those aged 60 and above, and male patients appeared to have a lower risk of developing symptomatic orthostatic hypotension, with hazard ratios of 0.38 and 0.56 respectively. Because aging is normally associated with an increased risk of the condition, the researchers interpret this apparent protective effect with considerable caution. They suggest it most likely reflects bias rather than biology: older adults often have diminished awareness of symptoms related to reduced cerebral blood flow and may report falls rather than typical complaints such as dizziness, while retrospective designs introduce ascertainment and detection biases. Older patients may also have been less likely to receive outpatient therapy, which was itself the strongest risk factor. The authors label this observation hypothesis-generating and call for prospective confirmation.
Notably, the occurrence of orthostatic hypotension did not translate into measurable differences in hard clinical outcomes. Among the 278 hospitalized patients, there were no statistically significant differences between those who did and did not develop the condition in relapse rates, non-relapse mortality, or overall survival at 100 days and one year. The study also found no significant association between orthostatic hypotension and fall events, though only ten falls occurred across the entire cohort, leaving the analysis underpowered to detect such a link. Nine of the ten patients who fell had experienced weight loss exceeding 2 percent before or shortly after the fall, and routine interventions, including bed-exit alarms for inpatients and fluid supplementation for affected patients, may have suppressed fall rates even among those with the condition. The absence of statistical significance, the authors emphasize, should not be read as evidence of no association.
The practical implications of the study are straightforward and potentially transformative for supportive care in hematology. The researchers recommend incorporating active orthostatic vital sign measurement, meaning supine and standing blood pressure and heart rate, into routine assessment during and after cellular therapy, ideally at least daily during the highest-risk early post-infusion period and at every outpatient visit. Patients found to have orthostatic hypotension can be managed with a stepwise approach that includes reviewing and, where appropriate, temporarily reducing antihypertensive medications, oral or intravenous fluid repletion guided by daily weights, patient education about slow positional changes and adequate fluid and salt intake, and fall prevention measures. Those with symptomatic or recurrent episodes, or patients being managed as outpatients, may warrant closer monitoring and a lower threshold for preemptive fluid support. These recommendations align with current cardio-oncology guidance from the American Heart Association and European Society of Cardiology on recognizing and managing autonomic dysfunction in patients with cancer. As cellular therapies continue to expand into new cancers and earlier lines of treatment, the humble blood pressure cuff may prove to be one of the most important tools in protecting patients through their recovery.
Subject of Research: Orthostatic hypotension incidence and risk factors in patients receiving hematopoietic cell transplantation and CAR-T cellular therapy
Article Title: Unmasking orthostatic hypotension after cellular therapy: risk factors, implications, and clinical significance
Article References: Vazquez-Urrutia, J. R., Santucci, J., Modgil, P., Lal, A., Inoue, Y., Zimmerman, J., Woodworth, R., Knol, K., Hess, E., Jordan, J., Stover, J., Rekawek, E., Cioccio, J., Rakszawski, K., Songdej, N., Nickolich, M., Zheng, H., Naik, S., Ehmann, C., … Minagawa, K. (2026). Unmasking orthostatic hypotension after cellular therapy: risk factors, implications, and clinical significance. Supportive Care in Cancer, 34(10), Article 1023. https://doi.org/10.1007/s00520-026-11247-z
Image Credits: AI Generated
DOI: 10.1007/s00520-026-11247-z
Keywords: orthostatic hypotension, cellular therapy, hematopoietic cell transplantation, CAR-T therapy, blood pressure, falls, weight loss, infection, outpatient care, supportive care, autonomic dysfunction, oncology
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Nathaniel Bowman. (September 26, 2026). Dizzy Spells After Cell Therapy: Study Finds Most Patients Suffer Hidden Blood Pressure Drops. Scienmag. https://scienmag.com/dizzy-spells-after-cell-therapy-study-finds-most-patients-suffer-hidden-blood-pressure-drops/
Nathaniel Bowman. “Dizzy Spells After Cell Therapy: Study Finds Most Patients Suffer Hidden Blood Pressure Drops.” Scienmag, 26 September 2026, https://scienmag.com/dizzy-spells-after-cell-therapy-study-finds-most-patients-suffer-hidden-blood-pressure-drops/. Accessed 26 September 2026.
Nathaniel Bowman. “Dizzy Spells After Cell Therapy: Study Finds Most Patients Suffer Hidden Blood Pressure Drops.” Scienmag. September 26, 2026. https://scienmag.com/dizzy-spells-after-cell-therapy-study-finds-most-patients-suffer-hidden-blood-pressure-drops/
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Tags: autonomic dysfunctionblood pressureblood pressure drops after cellular treatmentsblood pressure regulation during cell therapyCAR-T therapycardiovascular complications in cancer treatmentscell therapy side effectscellular therapyclinical significance of blood pressure fluctuations post-treatmentdizziness and fainting post-cell therapyfallshematopoietic cell transplantationimpact of cellular therapies on autonomic nervous systeminfectionmanagement of blood pressure drops after cellular treatmentsoncologyorthostatic hypotensionoutpatient careprevalence of orthostatic hypotension in cancer patientsrisk factors for orthostatic hypotensionsupportive caresymptoms of post-treatment blood pressure issuesweight loss
