AT IHC 2015

VALENCIA, SPAIN (FRONTLINE MEDICAL NEWS) – Inpatient high-dose intravenous dihydroergotamine delivered through a peripherally inserted central catheter or midline catheter for treatment of refractory headache appears to be associated with an increased risk of venous thrombosis, according to a retrospective case-control study.

“In patients with PICC or midline catheter placement, a low threshold for consideration of ultrasound investigation and consideration of prophylactic anticoagulation are appropriate. But patients with peripheral IVs had a very low thrombosis rate, so it seems reasonable to continue not to anticoagulate these patients,” Dr. Amy Tso said at the International Headache Congress.

Most headache centers rely upon a 5-day inpatient course of IV dihydroergotamine (DHE) as their workhorse therapy for the most refractory patients with chronic migraine or chronic cluster headache. But at the Headache Center of the University of California, San Francisco, where this internationally popular regimen was pioneered ( Neurology 2011;77:1827-32 ), investigators have concluded that the risk of venous thrombosis when the drug is delivered by PICC or midline catheter is suspiciously high in what is a generally healthy ambulatory patient population aside from their severe headaches.

Dr. Tso, a neurologist at the university, presented a new retrospective analysis of 604 consecutive admissions for this therapy in 450 adult and pediatric patients. ‘Venous thrombosis occurred in 6.8% of 264 severe headache patients whose dihydroergotamine was administered through a PICC line or midline catheter. The venous thrombosis rate was 6.4% in 157 patients treated through a PICC line and 7.5% in 107 whose DHE was given through a midline catheter. Eleven of the 18 affected patients had deep vein thrombosis warranting 3 months of oral anticoagulation, and 2 others developed pulmonary embolism.

In contrast, venous thrombosis occurred in 1 of 272 patients treated via a peripheral IV line.

In this study, venous thrombosis risk was unrelated to total DHE dose, age, gender, or the presence or absence of aura.

Since most studies of VTE risk in patients with a PICC or midline catheter have been conducted in cancer patients getting chemotherapy, patients on antibiotics for serious infections, or individuals on total parenteral nutrition – populations very different from headache patients – Dr. Tso opted to use as a control group for her study of 56 headache patients who received a 10-day inpatient course of IV lidocaine at the UCSF Headache Center; not one of them developed venous thrombosis, regardless of whether the lidocaine was given through a PICC, peripheral IV line, or midline catheter, she reported at the meeting, which was sponsored by the International Headache Society and the American Headache Society.

Physicians routinely use a peripheral IV line at the start of the 5-day course of inpatient DHE, during which patients receive 1 mg of the drug every 8 hours. However, DHE is a potent vasoconstrictor, and when the veins clamp down, as occurs often, it’s common practice to switch to a PICC or midline catheter to maintain vascular access and continue treatment.

“I certainly don’t think this new information about venous thrombosis risk would lead us to not give the therapy. The data supporting the use of this protocol in treating chronic migraine and chronic cluster headache have established that it’s so useful,” she said in an interview. “But I’ll have more reticence to put in a central line, and when I do I’ll have a lower threshold for getting an ultrasound when a patient complains of discomfort.”

Dr. Tso reported having no financial conflicts regarding this study.