A 59-year-old woman with a 10-year history of type 2 diabetes mellitus is noted by her physician to have bilateral pitting edema of the ankles and feet. No erythema is noted. On questioning, the patient also repos shoness of breath on exeion and states that she has been using 3 pillows at night in order to sleep comfoably. A chest x-ray film demonstrates pulmonary venous congestion and interstitial edema indicative of pulmonary edema. Which of the following physiologic mechanisms is most likely the immediate cause of the pulmonary edema?