IN JUNE, 5 months after leaving #La_Rinconada, Vergès’s team presented some startling preliminary results at a high-altitude physiology meeting in Chamonix. Compared with 20 Peruvians living at sea level and another 20 from 3800 meters, the La Rinconada miners had colossal amounts of hemoglobin in their blood. Some carried more than 2 kilograms, the highest values ever reported, Vergès says. (Lowlanders living in Lima, by comparison, on average had 747 grams.) But contrary to his expectations—and what most hypotheses about CMS would predict—hemoglobin mass wasn’t significantly higher in men with CMS than in those without.
One factor that did correlate with CMS, however, was blood viscosity: People with thicker blood were more likely to suffer from the syndrome. Taken together, those two findings led Vergès to speculate that in some people, the physical properties of their red cells lower blood viscosity and their risk of CMS. Perhaps their size or flexibility makes the cells flow better, he said. It was grist for a follow-up study.
The team also reported pulmonary blood pressure, which in healthy people is about 15 millimeters of mercury (mmHg). In CMS sufferers, it rose to some 30 mmHg during rest and up to 50 mmHg during exercise. “Those are crazy values,” Vergès says. “You can hardly believe how the capillaries in the lungs can tolerate such pressure.”
Electrocardiography showed that such high pressure affects the heart dramatically: The right ventricle—which pumps blood to the lungs through the pulmonary artery—expands, and its wall thickens. “The next question is what long-term effects this has on the heart,” Vergès said. The team is still working through reams of other data, including those on genetics and epigenetics. But Vergès is already planning another trip to La Rinconada, in February 2020.
