How many die every year due to lack of access to adequate health care according to your research?
The research shows that people died for lack of health insurance, not for lack of health care. People can still receive health care, even without insurance. All these people obtaining insurance (at a massive cost to the taxpayer) will not simply save all of those people, though. Further, this will lead to a supply and demand situation leaving others to go without care when needed and them to suffer (and die) because of it, even though they had insurance.
There are over 2.5 million deaths per yer in America. If "45 thousand" of them (number from the Harvard study you're likely referencing) is because of lack of access to adequate health care (lack of health insurance in the study), then we're only talking about less than 2% of all the deaths in this country. And that number is across all age bands, including those age 65 or more, which wouldn't be covered by the ACA.
Roughly 14 times as many people die from heart disease, and 13 times as many die from cancer each year. Even in today's day and age, more people die from pneumonia and influenza than die from "lack of adequate health care access". Just to put that number into perspective a bit, if you're to believe it 100%, which I don't.