Natalie Cole's family have named heart failure as the singer's cause of death, stemming from her suffering from the condition idiopathic pulmonary arterial hypertension. The singer - who is the daughter of Nat King Cole and Maria Cole - tragically passed away at the age of 65 on New Year’s Eve in a hospital in Los Angeles.In a statement, Cole’s family explained the reasons for her passing, saying she suffered from idiopathic pulmonary arterial hypertension after undergoing a kidney transplant in 2009.This, in turn, led to the heart failure that caused Natalie’s death.The statement read: “[Cole] responded well to pulmonary arterial hypertension-specific agents over many years, during which she performed many concerts world-wide, but eventually succumbed to intractable right heart failure, an outcome that unfortunately commonly occurs in this progressive disorder."Cole had to have the kidney transplant after battling hepatitis and drug problems earlier in her life.Cole's death was announced in a statement from her siblings and son Robert Yancy.They said: "It is with heavy hearts that we bring to you all the news of our Mother and sister's passing. Natalie fought a fierce, courageous battle, dying how she lived ... with dignity, strength and honor. Our beloved Mother and sister will be greatly missed and remain UNFORGETTABLE in our hearts forever. (sic)"..